21252686 has 32 divisors (see below), whose sum is σ = 41549760. Its totient is φ = 7911936.

The previous prime is 21252677. The next prime is 21252691. The reversal of 21252686 is 68625212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 341 + ... + 6528.

It is an arithmetic number, because the mean of its divisors is an integer number (1298430).

Almost surely, 2^21252686 is an apocalyptic number.

21252686 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21252686 is a deficient number, since it is larger than the sum of its proper divisors (20297074).

21252686 is a wasteful number, since it uses less digits than its factorization.

21252686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6908.

The product of its digits is 11520, while the sum is 32.

The square root of 21252686 is about 4610.0635570456. The cubic root of 21252686 is about 276.9945825594.

Adding to 21252686 its reverse (68625212), we get a palindrome (89877898).

The spelling of 21252686 in words is "twenty-one million, two hundred fifty-two thousand, six hundred eighty-six".