21922731 has 12 divisors (see below), whose sum is σ = 32839352. Its totient is φ = 14614992.

The previous prime is 21922723. The next prime is 21922739. The reversal of 21922731 is 13722912.

It is an interprime number because it is at equal distance from previous prime (21922723) and next prime (21922739).

It is not a de Polignac number, because 21922731 - 2³ = 21922723 is a prime.

It is a super-2 number, since 2×21922731² = 961212268996722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21922695 and 21922704.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21922739) 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 11 ways as a sum of consecutive naturals, for example, 44866 + ... + 45351.

Almost surely, 2^21922731 is an apocalyptic number.

21922731 is a deficient number, since it is larger than the sum of its proper divisors (10916621).

21922731 is an frugal number, since it uses more digits than its factorization.

21922731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90232 (or 90220 counting only the distinct ones).

The product of its digits is 1512, while the sum is 27.

The square root of 21922731 is about 4682.1716115495. The cubic root of 21922731 is about 279.8755016244.

The spelling of 21922731 in words is "twenty-one million, nine hundred twenty-two thousand, seven hundred thirty-one".