166221631 has 8 divisors (see below), whose sum is σ = 176159664. Its totient is φ = 156301440.

The previous prime is 166221623. The next prime is 166221637. The reversal of 166221631 is 136122661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 166221631 - 2³ = 166221623 is a prime.

It is a super-2 number, since 2×166221631² = 55259261224600322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 166221631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166221637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18001 + ... + 25621.

It is an arithmetic number, because the mean of its divisors is an integer number (22019958).

Almost surely, 2^166221631 is an apocalyptic number.

166221631 is a deficient number, since it is larger than the sum of its proper divisors (9938033).

166221631 is a wasteful number, since it uses less digits than its factorization.

166221631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8921.

The product of its digits is 2592, while the sum is 28.

The square root of 166221631 is about 12892.6968086588. The cubic root of 166221631 is about 549.8309463904.

The spelling of 166221631 in words is "one hundred sixty-six million, two hundred twenty-one thousand, six hundred thirty-one".