21922861 has 4 divisors (see below), whose sum is σ = 21988252. Its totient is φ = 21857472.

The previous prime is 21922853. The next prime is 21922889. The reversal of 21922861 is 16822912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2869636 + 19053225 = 1694^2 + 4365^2 .

It is a cyclic number.

It is not a de Polignac number, because 21922861 - 2³ = 21922853 is a prime.

It is a super-2 number, since 2×21922861² = 961223668850642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21922261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32190 + ... + 32863.

It is an arithmetic number, because the mean of its divisors is an integer number (5497063).

Almost surely, 2^21922861 is an apocalyptic number.

It is an amenable number.

21922861 is a deficient number, since it is larger than the sum of its proper divisors (65391).

21922861 is an equidigital number, since it uses as much as digits as its factorization.

21922861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65390.

The product of its digits is 3456, while the sum is 31.

The square root of 21922861 is about 4682.1854939761. The cubic root of 21922861 is about 279.8760548362.

The spelling of 21922861 in words is "twenty-one million, nine hundred twenty-two thousand, eight hundred sixty-one".