21646525624661 has 8 divisors (see below), whose sum is σ = 24738914826240. Its totient is φ = 18554143522608.

The previous prime is 21646525624637. The next prime is 21646525624679. The reversal of 21646525624661 is 16642652564612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21646525624661 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21646525624597 and 21646525624606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21646525624561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9733100 + ... + 11748458.

It is an arithmetic number, because the mean of its divisors is an integer number (3092364353280).

Almost surely, 2^{21646525624661} is an apocalyptic number.

It is an amenable number.

21646525624661 is a deficient number, since it is larger than the sum of its proper divisors (3092389201579).

21646525624661 is a wasteful number, since it uses less digits than its factorization.

21646525624661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3549763.

The product of its digits is 24883200, while the sum is 56.

The spelling of 21646525624661 in words is "twenty-one trillion, six hundred forty-six billion, five hundred twenty-five million, six hundred twenty-four thousand, six hundred sixty-one".