21249552 has 20 divisors (see below), whose sum is σ = 54894800. Its totient is φ = 7083168.

The previous prime is 21249523. The next prime is 21249559. The reversal of 21249552 is 25594212.

It is not an unprimeable number, because it can be changed into a prime (21249559) 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, 221302 + ... + 221397.

It is an arithmetic number, because the mean of its divisors is an integer number (2744740).

Almost surely, 2^21249552 is an apocalyptic number.

It is an amenable number.

21249552 is an abundant number, since it is smaller than the sum of its proper divisors (33645248).

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

21249552 is a wasteful number, since it uses less digits than its factorization.

21249552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 442710 (or 442704 counting only the distinct ones).

The product of its digits is 7200, while the sum is 30.

The square root of 21249552 is about 4609.7236359678. The cubic root of 21249552 is about 276.9809663402.

The spelling of 21249552 in words is "twenty-one million, two hundred forty-nine thousand, five hundred fifty-two".