21636436446540 has 120 divisors (see below), whose sum is σ = 67936407129360. Its totient is φ = 5764437124992.

The previous prime is 21636436446503. The next prime is 21636436446593. The reversal of 21636436446540 is 4564463463612.

21636436446540 is a `hidden beast` number, since 2 + 1 + 6 + 3 + 64 + 36 + 4 + 4 + 6 + 540 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 4339050 + ... + 7880369.

It is an arithmetic number, because the mean of its divisors is an integer number (566136726078).

Almost surely, 2^{21636436446540} is an apocalyptic number.

21636436446540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21636436446540 is an abundant number, since it is smaller than the sum of its proper divisors (46299970682820).

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

21636436446540 is a wasteful number, since it uses less digits than its factorization.

21636436446540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12220533 (or 12220522 counting only the distinct ones).

The product of its (nonzero) digits is 29859840, while the sum is 54.

The spelling of 21636436446540 in words is "twenty-one trillion, six hundred thirty-six billion, four hundred thirty-six million, four hundred forty-six thousand, five hundred forty".