21979131 has 8 divisors (see below), whose sum is σ = 29475600. Its totient is φ = 14567712.

The previous prime is 21979121. The next prime is 21979151. The reversal of 21979131 is 13197912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21979131 - 2⁷ = 21979003 is a prime.

It is a super-2 number, since 2×21979131² = 966164399030322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21979092 and 21979101.

It is not an unprimeable number, because it can be changed into a prime (21979121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20656 + ... + 21693.

It is an arithmetic number, because the mean of its divisors is an integer number (3684450).

Almost surely, 2^21979131 is an apocalyptic number.

21979131 is a deficient number, since it is larger than the sum of its proper divisors (7496469).

21979131 is a wasteful number, since it uses less digits than its factorization.

21979131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42525.

The product of its digits is 3402, while the sum is 33.

The square root of 21979131 is about 4688.1905891292. The cubic root of 21979131 is about 280.1153054013.

The spelling of 21979131 in words is "twenty-one million, nine hundred seventy-nine thousand, one hundred thirty-one".