21812319 has 24 divisors (see below), whose sum is σ = 32555952. Its totient is φ = 14065920.

The previous prime is 21812279. The next prime is 21812353. The reversal of 21812319 is 91321812.

It is not a de Polignac number, because 21812319 - 2¹⁶ = 21746783 is a prime.

It is a super-2 number, since 2×21812319² = 951554520315522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21812292 and 21812301.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21812389) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 36487 + ... + 37079.

It is an arithmetic number, because the mean of its divisors is an integer number (1356498).

Almost surely, 2^21812319 is an apocalyptic number.

21812319 is a deficient number, since it is larger than the sum of its proper divisors (10743633).

21812319 is a wasteful number, since it uses less digits than its factorization.

21812319 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 727 (or 724 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The square root of 21812319 is about 4670.3660456114. The cubic root of 21812319 is about 279.4048540984.

The spelling of 21812319 in words is "twenty-one million, eight hundred twelve thousand, three hundred nineteen".