21590493 has 16 divisors (see below), whose sum is σ = 30588480. Its totient is φ = 13499136.

The previous prime is 21590431. The next prime is 21590501. The reversal of 21590493 is 39409512.

It is not a de Polignac number, because 21590493 - 2⁸ = 21590237 is a prime.

It is a super-2 number, since 2×21590493² = 932298775966098, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21590423) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18771 + ... + 19887.

It is an arithmetic number, because the mean of its divisors is an integer number (1911780).

Almost surely, 2^21590493 is an apocalyptic number.

It is an amenable number.

21590493 is a deficient number, since it is larger than the sum of its proper divisors (8997987).

21590493 is a wasteful number, since it uses less digits than its factorization.

21590493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1516.

The product of its (nonzero) digits is 9720, while the sum is 33.

The square root of 21590493 is about 4646.5571125297. The cubic root of 21590493 is about 278.4544651457.

The spelling of 21590493 in words is "twenty-one million, five hundred ninety thousand, four hundred ninety-three".