13656400820 has 24 divisors (see below), whose sum is σ = 29219546664. Its totient is φ = 5359492736.

The previous prime is 13656400801. The next prime is 13656400837. The reversal of 13656400820 is 2800465631.

It can be written as a sum of positive squares in 4 ways, for example, as 4519335076 + 9137065744 = 67226^2 + 95588^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6440639 + ... + 6442758.

It is an arithmetic number, because the mean of its divisors is an integer number (1217481111).

Almost surely, 2^13656400820 is an apocalyptic number.

13656400820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

13656400820 is an abundant number, since it is smaller than the sum of its proper divisors (15563145844).

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

13656400820 is a wasteful number, since it uses less digits than its factorization.

13656400820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12883459 (or 12883457 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 35.

The spelling of 13656400820 in words is "thirteen billion, six hundred fifty-six million, four hundred thousand, eight hundred twenty".