21060979 has 4 divisors (see below), whose sum is σ = 21177520. Its totient is φ = 20944440.

The previous prime is 21060967. The next prime is 21061009. The reversal of 21060979 is 97906012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21060979 - 2⁵ = 21060947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21060929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57999 + ... + 58360.

It is an arithmetic number, because the mean of its divisors is an integer number (5294380).

Almost surely, 2^21060979 is an apocalyptic number.

21060979 is a deficient number, since it is larger than the sum of its proper divisors (116541).

21060979 is a wasteful number, since it uses less digits than its factorization.

21060979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116540.

The product of its (nonzero) digits is 6804, while the sum is 34.

The square root of 21060979 is about 4589.2242263808. The cubic root of 21060979 is about 276.1592015429.

The spelling of 21060979 in words is "twenty-one million, sixty thousand, nine hundred seventy-nine".