20409434656 has 48 divisors (see below), whose sum is σ = 43981356888. Its totient is φ = 9265305600.

The previous prime is 20409434623. The next prime is 20409434663. The reversal of 20409434656 is 65643490402.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 4749415056 + 15660019600 = 68916^2 + 125140^2 .

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, 376765 + ... + 427516.

Almost surely, 2^20409434656 is an apocalyptic number.

20409434656 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

20409434656 is an abundant number, since it is smaller than the sum of its proper divisors (23571922232).

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

20409434656 is a wasteful number, since it uses less digits than its factorization.

20409434656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 804365 (or 804357 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 43.

The spelling of 20409434656 in words is "twenty billion, four hundred nine million, four hundred thirty-four thousand, six hundred fifty-six".