21387231366 has 32 divisors (see below), whose sum is σ = 43267205376. Its totient is φ = 7047180000.

The previous prime is 21387231347. The next prime is 21387231367. The reversal of 21387231366 is 66313278312.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21387231367) 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, 354421 + ... + 410351.

It is an arithmetic number, because the mean of its divisors is an integer number (1352100168).

Almost surely, 2^21387231366 is an apocalyptic number.

21387231366 is an abundant number, since it is smaller than the sum of its proper divisors (21879974010).

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

21387231366 is a wasteful number, since it uses less digits than its factorization.

21387231366 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56668.

The product of its digits is 217728, while the sum is 42.

The spelling of 21387231366 in words is "twenty-one billion, three hundred eighty-seven million, two hundred thirty-one thousand, three hundred sixty-six".