20436421656 has 64 divisors (see below), whose sum is σ = 60928473600. Its totient is φ = 5585107968.

The previous prime is 20436421639. The next prime is 20436421661. The reversal of 20436421656 is 65612463402.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2640601 + ... + 2648328.

It is an arithmetic number, because the mean of its divisors is an integer number (952007400).

Almost surely, 2^20436421656 is an apocalyptic number.

It is an amenable number.

20436421656 is an abundant number, since it is smaller than the sum of its proper divisors (40492051944).

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

20436421656 is a wasteful number, since it uses less digits than its factorization.

20436421656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5288968 (or 5288964 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 39.

The spelling of 20436421656 in words is "twenty billion, four hundred thirty-six million, four hundred twenty-one thousand, six hundred fifty-six".