21249624 has 32 divisors (see below), whose sum is σ = 57954240. Its totient is φ = 6439200.

The previous prime is 21249623. The next prime is 21249637. The reversal of 21249624 is 42694212.

It is a junction number, because it is equal to n+sod(n) for n = 21249591 and 21249600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21249623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39982 + ... + 40509.

It is an arithmetic number, because the mean of its divisors is an integer number (1811070).

Almost surely, 2^21249624 is an apocalyptic number.

21249624 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21249624 is an abundant number, since it is smaller than the sum of its proper divisors (36704616).

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

21249624 is a wasteful number, since it uses less digits than its factorization.

21249624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80511 (or 80507 counting only the distinct ones).

The product of its digits is 6912, while the sum is 30.

The square root of 21249624 is about 4609.7314455400. The cubic root of 21249624 is about 276.9812791720.

The spelling of 21249624 in words is "twenty-one million, two hundred forty-nine thousand, six hundred twenty-four".