21922791 has 16 divisors (see below), whose sum is σ = 32175360. Its totient is φ = 13166720.

The previous prime is 21922787. The next prime is 21922799. The reversal of 21922791 is 19722912.

It is a cyclic number.

It is not a de Polignac number, because 21922791 - 2² = 21922787 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21922799) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 790 + ... + 6668.

It is an arithmetic number, because the mean of its divisors is an integer number (2010960).

Almost surely, 2^21922791 is an apocalyptic number.

21922791 is a deficient number, since it is larger than the sum of its proper divisors (10252569).

21922791 is a wasteful number, since it uses less digits than its factorization.

21922791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6006.

The product of its digits is 4536, while the sum is 33.

The square root of 21922791 is about 4682.1780188284. The cubic root of 21922791 is about 279.8757569532.

The spelling of 21922791 in words is "twenty-one million, nine hundred twenty-two thousand, seven hundred ninety-one".