21249160 has 16 divisors (see below), whose sum is σ = 47810700. Its totient is φ = 8499648.

The previous prime is 21249157. The next prime is 21249161. The reversal of 21249160 is 6194212.

It can be written as a sum of positive squares in 2 ways, for example, as 21178404 + 70756 = 4602^2 + 266^2 .

It is not an unprimeable number, because it can be changed into a prime (21249161) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 265575 + ... + 265654.

Almost surely, 2^21249160 is an apocalyptic number.

21249160 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21249160 is an abundant number, since it is smaller than the sum of its proper divisors (26561540).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21249160 is a wasteful number, since it uses less digits than its factorization.

21249160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 531240 (or 531236 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 21249160 is about 4609.6811169538. The cubic root of 21249160 is about 276.9792631324.

The spelling of 21249160 in words is "twenty-one million, two hundred forty-nine thousand, one hundred sixty".