21939927 has 32 divisors (see below), whose sum is σ = 32248320. Its totient is φ = 13219200.

The previous prime is 21939919. The next prime is 21939937. The reversal of 21939927 is 72993912.

It is a happy number.

It is not a de Polignac number, because 21939927 - 2³ = 21939919 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21939937) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 212958 + ... + 213060.

It is an arithmetic number, because the mean of its divisors is an integer number (1007760).

Almost surely, 2^21939927 is an apocalyptic number.

21939927 is a deficient number, since it is larger than the sum of its proper divisors (10308393).

21939927 is a wasteful number, since it uses less digits than its factorization.

21939927 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263.

The product of its digits is 61236, while the sum is 42.

The square root of 21939927 is about 4684.0075789862. The cubic root of 21939927 is about 279.9486598046.

The spelling of 21939927 in words is "twenty-one million, nine hundred thirty-nine thousand, nine hundred twenty-seven".