21931339 has 8 divisors (see below), whose sum is σ = 23365440. Its totient is φ = 20525256.

The previous prime is 21931331. The next prime is 21931361. The reversal of 21931339 is 93313912.

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

It is a cyclic number.

It is not a de Polignac number, because 21931339 - 2³ = 21931331 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21931339.

It is not an unprimeable number, because it can be changed into a prime (21931331) 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, 5377 + ... + 8530.

It is an arithmetic number, because the mean of its divisors is an integer number (2920680).

Almost surely, 2^21931339 is an apocalyptic number.

21931339 is a deficient number, since it is larger than the sum of its proper divisors (1434101).

21931339 is a wasteful number, since it uses less digits than its factorization.

21931339 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14009.

The product of its digits is 4374, while the sum is 31.

The square root of 21931339 is about 4683.0907529109. The cubic root of 21931339 is about 279.9121280384.

The spelling of 21931339 in words is "twenty-one million, nine hundred thirty-one thousand, three hundred thirty-nine".