21389610 has 32 divisors (see below), whose sum is σ = 56002752. Its totient is φ = 5185280.

The previous prime is 21389593. The next prime is 21389629. The reversal of 21389610 is 1698312.

It is a Harshad number since it is a multiple of its sum of digits (30).

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, 32079 + ... + 32738.

It is an arithmetic number, because the mean of its divisors is an integer number (1750086).

Almost surely, 2^21389610 is an apocalyptic number.

21389610 is an abundant number, since it is smaller than the sum of its proper divisors (34613142).

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

21389610 is a wasteful number, since it uses less digits than its factorization.

21389610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64838.

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 21389610 is about 4624.8902689686. The cubic root of 21389610 is about 277.5881709920.

The spelling of 21389610 in words is "twenty-one million, three hundred eighty-nine thousand, six hundred ten".