21564649707 has 8 divisors (see below), whose sum is σ = 29016654480. Its totient is φ = 14244539040.

The previous prime is 21564649679. The next prime is 21564649709. The reversal of 21564649707 is 70794646512.

It is a happy number.

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

It is not a de Polignac number, because 21564649707 - 2⁶ = 21564649643 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21564649707.

It is not an unprimeable number, because it can be changed into a prime (21564649709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32973144 + ... + 32973797.

It is an arithmetic number, because the mean of its divisors is an integer number (3627081810).

Almost surely, 2^21564649707 is an apocalyptic number.

21564649707 is a deficient number, since it is larger than the sum of its proper divisors (7452004773).

21564649707 is a wasteful number, since it uses less digits than its factorization.

21564649707 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65947053.

The product of its (nonzero) digits is 2540160, while the sum is 51.

The spelling of 21564649707 in words is "twenty-one billion, five hundred sixty-four million, six hundred forty-nine thousand, seven hundred seven".