21210569990 has 16 divisors (see below), whose sum is σ = 38572625952. Its totient is φ = 8396761344.

The previous prime is 21210569987. The next prime is 21210569999. The reversal of 21210569990 is 9996501212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210569999) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10932314 + ... + 10934253.

It is an arithmetic number, because the mean of its divisors is an integer number (2410789122).

Almost surely, 2^21210569990 is an apocalyptic number.

21210569990 is a deficient number, since it is larger than the sum of its proper divisors (17362055962).

21210569990 is a wasteful number, since it uses less digits than its factorization.

21210569990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21866671.

The product of its (nonzero) digits is 87480, while the sum is 44.

The spelling of 21210569990 in words is "twenty-one billion, two hundred ten million, five hundred sixty-nine thousand, nine hundred ninety".