12536561664 has 360 divisors, whose sum is σ = 40484283840. Its totient is φ = 3706060800.

The previous prime is 12536561663. The next prime is 12536561669. The reversal of 12536561664 is 46616563521.

12536561664 is a `hidden beast` number, since 1 + 2 + 536 + 56 + 1 + 6 + 64 = 666.

It is not an unprimeable number, because it can be changed into a prime (12536561663) by changing a digit.

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, 95698879 + ... + 95699009.

It is an arithmetic number, because the mean of its divisors is an integer number (112456344).

Almost surely, 2^12536561664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 12536561664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20242141920).

12536561664 is an abundant number, since it is smaller than the sum of its proper divisors (27947722176).

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

12536561664 is a wasteful number, since it uses less digits than its factorization.

12536561664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 235 (or 206 counting only the distinct ones).

The product of its digits is 777600, while the sum is 45.

It can be divided in two parts, 1253656 and 1664, that added together give a triangular number (1255320 = T₁₅₈₄).

The spelling of 12536561664 in words is "twelve billion, five hundred thirty-six million, five hundred sixty-one thousand, six hundred sixty-four".