21664542160 has 40 divisors (see below), whose sum is σ = 50555978496. Its totient is φ = 8633831040.

The previous prime is 21664542157. The next prime is 21664542173. The reversal of 21664542160 is 6124546612.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

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, 477964 + ... + 521323.

Almost surely, 2^21664542160 is an apocalyptic number.

21664542160 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21664542160 is an abundant number, since it is smaller than the sum of its proper divisors (28891436336).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21664542160 is a wasteful number, since it uses less digits than its factorization.

21664542160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 999571 (or 999565 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 37.

The spelling of 21664542160 in words is "twenty-one billion, six hundred sixty-four million, five hundred forty-two thousand, one hundred sixty".