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18020020 = 2252931069
BaseRepresentation
bin100010010111…
…1011010110100
31020220111211011
41010233122310
514103120040
61442122004
7306111334
oct104573264
936814734
1018020020
11a198787
126050304
13396c145
1425710c4
1518ae3ea
hex112f6b4

18020020 has 24 divisors (see below), whose sum is σ = 39148200. Its totient is φ = 6959232.

The previous prime is 18020011. The next prime is 18020027. The reversal of 18020020 is 2002081.

It can be written as a sum of positive squares in 4 ways, for example, as 2322576 + 15697444 = 1524^2 + 3962^2 .

It is a super-2 number, since 2×180200202 = 649442241600800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18020027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14955 + ... + 16114.

It is an arithmetic number, because the mean of its divisors is an integer number (1631175).

Almost surely, 218020020 is an apocalyptic number.

18020020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18020020 is an abundant number, since it is smaller than the sum of its proper divisors (21128180).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18020020 is a wasteful number, since it uses less digits than its factorization.

18020020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31107 (or 31105 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 18020020 is about 4244.9994110718. Note that the first 3 decimals coincide. The cubic root of 18020020 is about 262.1712649820.

The spelling of 18020020 in words is "eighteen million, twenty thousand, twenty".

Divisors: 1 2 4 5 10 20 29 58 116 145 290 580 31069 62138 124276 155345 310690 621380 901001 1802002 3604004 4505005 9010010 18020020