21152979 has 6 divisors (see below), whose sum is σ = 30554316. Its totient is φ = 14101980.

The previous prime is 21152969. The next prime is 21152983. The reversal of 21152979 is 97925112.

It is not a de Polignac number, because 21152979 - 2¹¹ = 21150931 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21152969) 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 5 ways as a sum of consecutive naturals, for example, 1175157 + ... + 1175174.

It is an arithmetic number, because the mean of its divisors is an integer number (5092386).

Almost surely, 2^21152979 is an apocalyptic number.

21152979 is a deficient number, since it is larger than the sum of its proper divisors (9401337).

21152979 is a wasteful number, since it uses less digits than its factorization.

21152979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2350337 (or 2350334 counting only the distinct ones).

The product of its digits is 11340, while the sum is 36.

The square root of 21152979 is about 4599.2367845111. The cubic root of 21152979 is about 276.5607299130.

The spelling of 21152979 in words is "twenty-one million, one hundred fifty-two thousand, nine hundred seventy-nine".