21811268 has 24 divisors (see below), whose sum is σ = 40346880. Its totient is φ = 10296000.

The previous prime is 21811261. The next prime is 21811351. The reversal of 21811268 is 86211812.

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21811268.

It is not an unprimeable number, because it can be changed into a prime (21811261) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5768 + ... + 8768.

It is an arithmetic number, because the mean of its divisors is an integer number (1681120).

Almost surely, 2^21811268 is an apocalyptic number.

It is an amenable number.

21811268 is a deficient number, since it is larger than the sum of its proper divisors (18535612).

21811268 is a wasteful number, since it uses less digits than its factorization.

21811268 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3107 (or 3105 counting only the distinct ones).

The product of its digits is 1536, while the sum is 29.

The square root of 21811268 is about 4670.2535263088. The cubic root of 21811268 is about 279.4003664322.

The spelling of 21811268 in words is "twenty-one million, eight hundred eleven thousand, two hundred sixty-eight".