21372313205 has 4 divisors (see below), whose sum is σ = 25646775852. Its totient is φ = 17097850560.

The previous prime is 21372313187. The next prime is 21372313217. The reversal of 21372313205 is 50231327312.

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

It can be written as a sum of positive squares in 2 ways, for example, as 14678291716 + 6694021489 = 121154^2 + 81817^2 .

It is not a de Polignac number, because 21372313205 - 2¹² = 21372309109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2137231316 + ... + 2137231325.

It is an arithmetic number, because the mean of its divisors is an integer number (6411693963).

Almost surely, 2^21372313205 is an apocalyptic number.

It is an amenable number.

21372313205 is a deficient number, since it is larger than the sum of its proper divisors (4274462647).

21372313205 is an equidigital number, since it uses as much as digits as its factorization.

21372313205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4274462646.

The product of its (nonzero) digits is 7560, while the sum is 29.

The spelling of 21372313205 in words is "twenty-one billion, three hundred seventy-two million, three hundred thirteen thousand, two hundred five".