21640566413 has 8 divisors (see below), whose sum is σ = 22207784256. Its totient is φ = 21075224800.

The previous prime is 21640566373. The next prime is 21640566433. The reversal of 21640566413 is 31466504612.

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

It is a cyclic number.

It is not a de Polignac number, because 21640566413 - 2⁶ = 21640566349 is a prime.

It is a super-2 number, since 2×21640566413² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21640566433) 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, 445673 + ... + 491838.

It is an arithmetic number, because the mean of its divisors is an integer number (2775973032).

Almost surely, 2^21640566413 is an apocalyptic number.

It is an amenable number.

21640566413 is a deficient number, since it is larger than the sum of its proper divisors (567217843).

21640566413 is an equidigital number, since it uses as much as digits as its factorization.

21640566413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 938115.

The product of its (nonzero) digits is 103680, while the sum is 38.

The spelling of 21640566413 in words is "twenty-one billion, six hundred forty million, five hundred sixty-six thousand, four hundred thirteen".