21249607 has 4 divisors (see below), whose sum is σ = 21258856. Its totient is φ = 21240360.

The previous prime is 21249589. The next prime is 21249623. The reversal of 21249607 is 70694212.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21249607 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21249637) 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, 1768 + ... + 6754.

It is an arithmetic number, because the mean of its divisors is an integer number (5314714).

Almost surely, 2^21249607 is an apocalyptic number.

21249607 is a deficient number, since it is larger than the sum of its proper divisors (9249).

21249607 is an equidigital number, since it uses as much as digits as its factorization.

21249607 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9248.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 21249607 is about 4609.7296016144. The cubic root of 21249607 is about 276.9812053090.

The spelling of 21249607 in words is "twenty-one million, two hundred forty-nine thousand, six hundred seven".