21912913 has 8 divisors (see below), whose sum is σ = 24194016. Its totient is φ = 19680000.

The previous prime is 21912907. The next prime is 21912931. The reversal of 21912913 is 31921912.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21912913 is a prime.

It is a super-2 number, since 2×21912913² = 960351512291138, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21912013) 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 7 ways as a sum of consecutive naturals, for example, 11088 + ... + 12913.

It is an arithmetic number, because the mean of its divisors is an integer number (3024252).

Almost surely, 2^21912913 is an apocalyptic number.

It is an amenable number.

21912913 is a deficient number, since it is larger than the sum of its proper divisors (2281103).

21912913 is a wasteful number, since it uses less digits than its factorization.

21912913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24095.

The product of its digits is 972, while the sum is 28.

The square root of 21912913 is about 4681.1230490129. The cubic root of 21912913 is about 279.8337150426.

The spelling of 21912913 in words is "twenty-one million, nine hundred twelve thousand, nine hundred thirteen".