20556939700 has 72 divisors (see below), whose sum is σ = 48868122240. Its totient is φ = 7443878400.

The previous prime is 20556939691. The next prime is 20556939749. The reversal of 20556939700 is 793965502.

It is a happy number.

It is a super-3 number, since 3×20556939700³ (a number of 32 digits) contains 333 as substring.

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 23 ways as a sum of consecutive naturals, for example, 223804 + ... + 301996.

It is an arithmetic number, because the mean of its divisors is an integer number (678723920).

Almost surely, 2^20556939700 is an apocalyptic number.

20556939700 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20556939700, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24434061120).

20556939700 is an abundant number, since it is smaller than the sum of its proper divisors (28311182540).

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

20556939700 is a wasteful number, since it uses less digits than its factorization.

20556939700 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78457 (or 78450 counting only the distinct ones).

The product of its (nonzero) digits is 510300, while the sum is 46.

The spelling of 20556939700 in words is "twenty billion, five hundred fifty-six million, nine hundred thirty-nine thousand, seven hundred".