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18856820 = 2259712
BaseRepresentation
bin100011111101…
…1101101110100
31022111000200202
41013323231310
514311404240
61512100032
7316165103
oct107735564
938430622
1018856820
11a70a454
126394618
133ba2ca8
14270c03a
1519c7315
hex11fbb74

18856820 has 18 divisors (see below), whose sum is σ = 39640146. Its totient is φ = 7534960.

The previous prime is 18856777. The next prime is 18856829. The reversal of 18856820 is 2865881.

It can be written as a sum of positive squares in only one way, i.e., 15085456 + 3771364 = 3884^2 + 1942^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18856829) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 18935 + ... + 19905.

Almost surely, 218856820 is an apocalyptic number.

18856820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18856820 is an abundant number, since it is smaller than the sum of its proper divisors (20783326).

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

18856820 is an frugal number, since it uses more digits than its factorization.

18856820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1951 (or 978 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 38.

The square root of 18856820 is about 4342.4440123046. Note that the first 3 decimals coincide. The cubic root of 18856820 is about 266.1681903133.

The spelling of 18856820 in words is "eighteen million, eight hundred fifty-six thousand, eight hundred twenty".

Divisors: 1 2 4 5 10 20 971 1942 3884 4855 9710 19420 942841 1885682 3771364 4714205 9428410 18856820