11565621540 has 72 divisors (see below), whose sum is σ = 38271699648. Its totient is φ = 2803786560.

The previous prime is 11565621521. The next prime is 11565621581. The reversal of 11565621540 is 4512656511.

11565621540 is a `hidden beast` number, since 1 + 1 + 56 + 5 + 62 + 1 + 540 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 11565621495 and 11565621504.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2918632 + ... + 2922591.

It is an arithmetic number, because the mean of its divisors is an integer number (531551384).

Almost surely, 2^11565621540 is an apocalyptic number.

11565621540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

11565621540 is an abundant number, since it is smaller than the sum of its proper divisors (26706078108).

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

11565621540 is a wasteful number, since it uses less digits than its factorization.

11565621540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5841249 (or 5841244 counting only the distinct ones).

The product of its (nonzero) digits is 36000, while the sum is 36.

The spelling of 11565621540 in words is "eleven billion, five hundred sixty-five million, six hundred twenty-one thousand, five hundred forty".