21249210 has 32 divisors (see below), whose sum is σ = 51166080. Its totient is φ = 5647808.

The previous prime is 21249203. The next prime is 21249253. The reversal of 21249210 is 1294212.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9784 + ... + 11756.

It is an arithmetic number, because the mean of its divisors is an integer number (1598940).

Almost surely, 2^21249210 is an apocalyptic number.

21249210 is an abundant number, since it is smaller than the sum of its proper divisors (29916870).

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

21249210 is a wasteful number, since it uses less digits than its factorization.

21249210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2342.

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 21249210 is about 4609.6865403192. The cubic root of 21249210 is about 276.9794803795.

The spelling of 21249210 in words is "twenty-one million, two hundred forty-nine thousand, two hundred ten".