221665170 has 16 divisors (see below), whose sum is σ = 531996480. Its totient is φ = 59110704.

The previous prime is 221665163. The next prime is 221665177. The reversal of 221665170 is 71566122.

It is an interprime number because it is at equal distance from previous prime (221665163) and next prime (221665177).

It is a super-2 number, since 2×221665170² = 98270895182257800, which contains 22 as substring.

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: 7388839 = 221665170 / (2 + 2 + 1 + 6 + 6 + 5 + 1 + 7 + 0).

It is not an unprimeable number, because it can be changed into a prime (221665177) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3694390 + ... + 3694449.

It is an arithmetic number, because the mean of its divisors is an integer number (33249780).

Almost surely, 2^221665170 is an apocalyptic number.

221665170 is an abundant number, since it is smaller than the sum of its proper divisors (310331310).

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

221665170 is a wasteful number, since it uses less digits than its factorization.

221665170 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7388849.

The product of its (nonzero) digits is 5040, while the sum is 30.

The square root of 221665170 is about 14888.4240267397. The cubic root of 221665170 is about 605.2003252561.

The spelling of 221665170 in words is "two hundred twenty-one million, six hundred sixty-five thousand, one hundred seventy".