21368990087 has 4 divisors (see below), whose sum is σ = 21369663696. Its totient is φ = 21368316480.

The previous prime is 21368990033. The next prime is 21368990143. The reversal of 21368990087 is 78009986312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21368990087 - 2¹² = 21368985991 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21368990287) 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 3 ways as a sum of consecutive naturals, for example, 286739 + ... + 353492.

It is an arithmetic number, because the mean of its divisors is an integer number (5342415924).

Almost surely, 2^21368990087 is an apocalyptic number.

21368990087 is a deficient number, since it is larger than the sum of its proper divisors (673609).

21368990087 is an equidigital number, since it uses as much as digits as its factorization.

21368990087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 673608.

The product of its (nonzero) digits is 1306368, while the sum is 53.

The spelling of 21368990087 in words is "twenty-one billion, three hundred sixty-eight million, nine hundred ninety thousand, eighty-seven".