21712959 has 6 divisors (see below), whose sum is σ = 31363176. Its totient is φ = 14475300.

The previous prime is 21712949. The next prime is 21712963. The reversal of 21712959 is 95921712.

It is not a de Polignac number, because 21712959 - 2²⁴ = 4935743 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21712939) 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 5 ways as a sum of consecutive naturals, for example, 1206267 + ... + 1206284.

It is an arithmetic number, because the mean of its divisors is an integer number (5227196).

Almost surely, 2^21712959 is an apocalyptic number.

21712959 is a deficient number, since it is larger than the sum of its proper divisors (9650217).

21712959 is a wasteful number, since it uses less digits than its factorization.

21712959 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2412557 (or 2412554 counting only the distinct ones).

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

The square root of 21712959 is about 4659.7166222851. The cubic root of 21712959 is about 278.9799577078.

The spelling of 21712959 in words is "twenty-one million, seven hundred twelve thousand, nine hundred fifty-nine".