21590731 has 8 divisors (see below), whose sum is σ = 23027760. Its totient is φ = 20172288.

The previous prime is 21590713. The next prime is 21590741. The reversal of 21590731 is 13709512.

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 21590731 - 2¹¹ = 21588683 is a prime.

It is a super-2 number, since 2×21590731² = 932319330228722, which contains 22 as substring.

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 21590731.

It is not an unprimeable number, because it can be changed into a prime (21590741) 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, 2206 + ... + 6931.

It is an arithmetic number, because the mean of its divisors is an integer number (2878470).

Almost surely, 2^21590731 is an apocalyptic number.

21590731 is a deficient number, since it is larger than the sum of its proper divisors (1437029).

21590731 is a wasteful number, since it uses less digits than its factorization.

21590731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9293.

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 21590731 is about 4646.5827228190. The cubic root of 21590731 is about 278.4554883109.

The spelling of 21590731 in words is "twenty-one million, five hundred ninety thousand, seven hundred thirty-one".