21207182399 has 4 divisors (see below), whose sum is σ = 22838504136. Its totient is φ = 19575860664.

The previous prime is 21207182387. The next prime is 21207182411. The reversal of 21207182399 is 99328170212.

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

It is an interprime number because it is at equal distance from previous prime (21207182387) and next prime (21207182411).

It is a cyclic number.

It is not a de Polignac number, because 21207182399 - 2⁴ = 21207182383 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 (21207482399) 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, 815660849 + ... + 815660874.

It is an arithmetic number, because the mean of its divisors is an integer number (5709626034).

Almost surely, 2^21207182399 is an apocalyptic number.

21207182399 is a deficient number, since it is larger than the sum of its proper divisors (1631321737).

21207182399 is a wasteful number, since it uses less digits than its factorization.

21207182399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1631321736.

The product of its (nonzero) digits is 108864, while the sum is 44.

The spelling of 21207182399 in words is "twenty-one billion, two hundred seven million, one hundred eighty-two thousand, three hundred ninety-nine".