21179870 has 24 divisors (see below), whose sum is σ = 40242744. Its totient is φ = 8024688.

The previous prime is 21179869. The next prime is 21179891. The reversal of 21179870 is 7897112.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21179870.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 677 + ... + 6543.

It is an arithmetic number, because the mean of its divisors is an integer number (1676781).

Almost surely, 2^21179870 is an apocalyptic number.

21179870 is a deficient number, since it is larger than the sum of its proper divisors (19062874).

21179870 is a wasteful number, since it uses less digits than its factorization.

21179870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5912 (or 5893 counting only the distinct ones).

The product of its (nonzero) digits is 7056, while the sum is 35.

The square root of 21179870 is about 4602.1592758183. The cubic root of 21179870 is about 276.6778740964.

The spelling of 21179870 in words is "twenty-one million, one hundred seventy-nine thousand, eight hundred seventy".