21496251 has 24 divisors (see below), whose sum is σ = 33529680. Its totient is φ = 12214272.

The previous prime is 21496247. The next prime is 21496273. The reversal of 21496251 is 15269412.

It is not a de Polignac number, because 21496251 - 2² = 21496247 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21496231) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 37495 + ... + 38063.

It is an arithmetic number, because the mean of its divisors is an integer number (1397070).

Almost surely, 2^21496251 is an apocalyptic number.

21496251 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21496251 is a deficient number, since it is larger than the sum of its proper divisors (12033429).

21496251 is a wasteful number, since it uses less digits than its factorization.

21496251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 843 (or 836 counting only the distinct ones).

The product of its digits is 4320, while the sum is 30.

The square root of 21496251 is about 4636.4049650564. The cubic root of 21496251 is about 278.0487251344.

The spelling of 21496251 in words is "twenty-one million, four hundred ninety-six thousand, two hundred fifty-one".