21409910 has 16 divisors (see below), whose sum is σ = 39358656. Its totient is φ = 8381568.

The previous prime is 21409909. The next prime is 21409931. The reversal of 21409910 is 1990412.

It is a self number, because there is not a number n which added to its sum of digits gives 21409910.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22307 + ... + 23246.

It is an arithmetic number, because the mean of its divisors is an integer number (2459916).

Almost surely, 2^21409910 is an apocalyptic number.

21409910 is a deficient number, since it is larger than the sum of its proper divisors (17948746).

21409910 is a wasteful number, since it uses less digits than its factorization.

21409910 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45607.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 21409910 is about 4627.0843951672. The cubic root of 21409910 is about 277.6759590684.

The spelling of 21409910 in words is "twenty-one million, four hundred nine thousand, nine hundred ten".