21590494 has 4 divisors (see below), whose sum is σ = 32385744. Its totient is φ = 10795246.

The previous prime is 21590431. The next prime is 21590501. The reversal of 21590494 is 49409512.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×21590494² = 932298862328072, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5397622 + ... + 5397625.

It is an arithmetic number, because the mean of its divisors is an integer number (8096436).

Almost surely, 2^21590494 is an apocalyptic number.

21590494 is a deficient number, since it is larger than the sum of its proper divisors (10795250).

21590494 is a wasteful number, since it uses less digits than its factorization.

21590494 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10795249.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 21590494 is about 4646.5572201362. The cubic root of 21590494 is about 278.4544694448.

It can be divided in two parts, 215 and 90494, that added together give a palindrome (90709).

The spelling of 21590494 in words is "twenty-one million, five hundred ninety thousand, four hundred ninety-four".