21664389190 has 32 divisors (see below), whose sum is σ = 41139900000. Its totient is φ = 8191346688.

The previous prime is 21664389179. The next prime is 21664389191. The reversal of 21664389190 is 9198346612.

It is a happy number.

It is a super-2 number, since 2×21664389190² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21664389191) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41665 + ... + 212284.

It is an arithmetic number, because the mean of its divisors is an integer number (1285621875).

Almost surely, 2^21664389190 is an apocalyptic number.

21664389190 is a deficient number, since it is larger than the sum of its proper divisors (19475510810).

21664389190 is a wasteful number, since it uses less digits than its factorization.

21664389190 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254424.

The product of its (nonzero) digits is 559872, while the sum is 49.

The spelling of 21664389190 in words is "twenty-one billion, six hundred sixty-four million, three hundred eighty-nine thousand, one hundred ninety".