21664824537 has 8 divisors (see below), whose sum is σ = 30406771360. Its totient is φ = 13683047040.

The previous prime is 21664824523. The next prime is 21664824553. The reversal of 21664824537 is 73542846612.

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

It is not a de Polignac number, because 21664824537 - 2⁸ = 21664824281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21664824557) 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, 190042264 + ... + 190042377.

It is an arithmetic number, because the mean of its divisors is an integer number (3800846420).

Almost surely, 2^21664824537 is an apocalyptic number.

It is an amenable number.

21664824537 is a deficient number, since it is larger than the sum of its proper divisors (8741946823).

21664824537 is a wasteful number, since it uses less digits than its factorization.

21664824537 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 380084663.

The product of its digits is 1935360, while the sum is 48.

The spelling of 21664824537 in words is "twenty-one billion, six hundred sixty-four million, eight hundred twenty-four thousand, five hundred thirty-seven".