21555922 has 16 divisors (see below), whose sum is σ = 34094592. Its totient is φ = 10200960.

The previous prime is 21555917. The next prime is 21555923. The reversal of 21555922 is 22955512.

It is not an unprimeable number, because it can be changed into a prime (21555923) 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, 2047 + ... + 6877.

It is an arithmetic number, because the mean of its divisors is an integer number (2130912).

Almost surely, 2^21555922 is an apocalyptic number.

21555922 is a deficient number, since it is larger than the sum of its proper divisors (12538670).

21555922 is a wasteful number, since it uses less digits than its factorization.

21555922 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4953.

The product of its digits is 9000, while the sum is 31.

The square root of 21555922 is about 4642.8355559938. The cubic root of 21555922 is about 278.3057640192.

The spelling of 21555922 in words is "twenty-one million, five hundred fifty-five thousand, nine hundred twenty-two".