21566022 has 16 divisors (see below), whose sum is σ = 43217472. Its totient is φ = 7174440.

The previous prime is 21566011. The next prime is 21566029. The reversal of 21566022 is 22066512.

It is a junction number, because it is equal to n+sod(n) for n = 21565983 and 21566001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21566029) 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, 4 + ... + 6567.

It is an arithmetic number, because the mean of its divisors is an integer number (2701092).

Almost surely, 2^21566022 is an apocalyptic number.

21566022 is an abundant number, since it is smaller than the sum of its proper divisors (21651450).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21566022 is a wasteful number, since it uses less digits than its factorization.

21566022 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7123.

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 21566022 is about 4643.9231259787. The cubic root of 21566022 is about 278.3492238369.

The spelling of 21566022 in words is "twenty-one million, five hundred sixty-six thousand, twenty-two".