21979107 has 24 divisors (see below), whose sum is σ = 33196800. Its totient is φ = 14531400.

The previous prime is 21979091. The next prime is 21979109. The reversal of 21979107 is 70197912.

It is not a de Polignac number, because 21979107 - 2⁴ = 21979091 is a prime.

It is a super-2 number, since 2×21979107² = 966162289034898, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21979109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 36394 + ... + 36992.

It is an arithmetic number, because the mean of its divisors is an integer number (1383200).

Almost surely, 2^21979107 is an apocalyptic number.

21979107 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21979107 is a deficient number, since it is larger than the sum of its proper divisors (11217693).

21979107 is an equidigital number, since it uses as much as digits as its factorization.

21979107 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 765 (or 753 counting only the distinct ones).

The product of its (nonzero) digits is 7938, while the sum is 36.

The square root of 21979107 is about 4688.1880295056. The cubic root of 21979107 is about 280.1152034444.

The spelling of 21979107 in words is "twenty-one million, nine hundred seventy-nine thousand, one hundred seven".