21372807 has 4 divisors (see below), whose sum is σ = 28497080. Its totient is φ = 14248536.

The previous prime is 21372787. The next prime is 21372811. The reversal of 21372807 is 70827312.

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

It is not a de Polignac number, because 21372807 - 2⁷ = 21372679 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 (21372887) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3562132 + ... + 3562137.

It is an arithmetic number, because the mean of its divisors is an integer number (7124270).

Almost surely, 2^21372807 is an apocalyptic number.

21372807 is a deficient number, since it is larger than the sum of its proper divisors (7124273).

21372807 is an equidigital number, since it uses as much as digits as its factorization.

21372807 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7124272.

The product of its (nonzero) digits is 4704, while the sum is 30.

The square root of 21372807 is about 4623.0733284256. The cubic root of 21372807 is about 277.5154637921.

The spelling of 21372807 in words is "twenty-one million, three hundred seventy-two thousand, eight hundred seven".