21973170 has 16 divisors (see below), whose sum is σ = 52735680. Its totient is φ = 5859504.

The previous prime is 21973169. The next prime is 21973181. The reversal of 21973170 is 7137912.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 732439 = 21973170 / (2 + 1 + 9 + 7 + 3 + 1 + 7 + 0).

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, 366190 + ... + 366249.

It is an arithmetic number, because the mean of its divisors is an integer number (3295980).

Almost surely, 2^21973170 is an apocalyptic number.

21973170 is an abundant number, since it is smaller than the sum of its proper divisors (30762510).

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

21973170 is a wasteful number, since it uses less digits than its factorization.

21973170 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 732449.

The product of its (nonzero) digits is 2646, while the sum is 30.

The square root of 21973170 is about 4687.5547996797. The cubic root of 21973170 is about 280.0899795849.

The spelling of 21973170 in words is "twenty-one million, nine hundred seventy-three thousand, one hundred seventy".