21979463 has 4 divisors (see below), whose sum is σ = 23977608. Its totient is φ = 19981320.

The previous prime is 21979457. The next prime is 21979469. The reversal of 21979463 is 36497912.

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

It is an interprime number because it is at equal distance from previous prime (21979457) and next prime (21979469).

It is a cyclic number.

It is not a de Polignac number, because 21979463 - 2¹⁴ = 21963079 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21979463.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21979469) 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, 999056 + ... + 999077.

It is an arithmetic number, because the mean of its divisors is an integer number (5994402).

Almost surely, 2^21979463 is an apocalyptic number.

21979463 is a deficient number, since it is larger than the sum of its proper divisors (1998145).

21979463 is a wasteful number, since it uses less digits than its factorization.

21979463 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1998144.

The product of its digits is 81648, while the sum is 41.

The square root of 21979463 is about 4688.2259971123. The cubic root of 21979463 is about 280.1167157970.

The spelling of 21979463 in words is "twenty-one million, nine hundred seventy-nine thousand, four hundred sixty-three".