21640697213 has 8 divisors (see below), whose sum is σ = 22919408640. Its totient is φ = 20362622400.

The previous prime is 21640697207. The next prime is 21640697219. The reversal of 21640697213 is 31279604612.

It is an interprime number because it is at equal distance from previous prime (21640697207) and next prime (21640697219).

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 21640697213 - 2¹² = 21640693117 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21640697219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 88253 + ... + 225986.

It is an arithmetic number, because the mean of its divisors is an integer number (2864926080).

Almost surely, 2^21640697213 is an apocalyptic number.

It is an amenable number.

21640697213 is a deficient number, since it is larger than the sum of its proper divisors (1278711427).

21640697213 is a wasteful number, since it uses less digits than its factorization.

21640697213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 318307.

The product of its (nonzero) digits is 108864, while the sum is 41.

The spelling of 21640697213 in words is "twenty-one billion, six hundred forty million, six hundred ninety-seven thousand, two hundred thirteen".