21372263 has 16 divisors (see below), whose sum is σ = 24205824. Its totient is φ = 18701760.

The previous prime is 21372233. The next prime is 21372269. The reversal of 21372263 is 36227312.

It is not a de Polignac number, because 21372263 - 2⁸ = 21372007 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 (21372269) 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 15 ways as a sum of consecutive naturals, for example, 34331 + ... + 34947.

It is an arithmetic number, because the mean of its divisors is an integer number (1512864).

Almost surely, 2^21372263 is an apocalyptic number.

21372263 is a deficient number, since it is larger than the sum of its proper divisors (2833561).

21372263 is a wasteful number, since it uses less digits than its factorization.

21372263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 742.

The product of its digits is 3024, while the sum is 26.

The square root of 21372263 is about 4623.0144927309. The cubic root of 21372263 is about 277.5131092473.

Adding to 21372263 its reverse (36227312), we get a palindrome (57599575).

The spelling of 21372263 in words is "twenty-one million, three hundred seventy-two thousand, two hundred sixty-three".