20505020 has 24 divisors (see below), whose sum is σ = 43491168. Its totient is φ = 8120000.

The previous prime is 20505007. The next prime is 20505031. The reversal of 20505020 is 2050502.

It is a junction number, because it is equal to n+sod(n) for n = 20504986 and 20505004.

It is a congruent number.

It is an unprimeable number.

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, 3056 + ... + 7095.

It is an arithmetic number, because the mean of its divisors is an integer number (1812132).

Almost surely, 2^20505020 is an apocalyptic number.

20505020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20505020 is an abundant number, since it is smaller than the sum of its proper divisors (22986148).

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

20505020 is a wasteful number, since it uses less digits than its factorization.

20505020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10261 (or 10259 counting only the distinct ones).

The product of its (nonzero) digits is 100, while the sum is 14.

The square root of 20505020 is about 4528.2469013957. The cubic root of 20505020 is about 273.7075217479.

Adding to 20505020 its reverse (2050502), we get a palindrome (22555522).

The spelling of 20505020 in words is "twenty million, five hundred five thousand, twenty".