166521613 has 8 divisors (see below), whose sum is σ = 176463360. Its totient is φ = 156596160.

The previous prime is 166521533. The next prime is 166521617. The reversal of 166521613 is 316125661.

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 166521613 - 2⁹ = 166521101 is a prime.

It is a super-2 number, since 2×166521613² = 55458895192243538, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166521617) 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, 21678 + ... + 28336.

It is an arithmetic number, because the mean of its divisors is an integer number (22057920).

Almost surely, 2^166521613 is an apocalyptic number.

It is an amenable number.

166521613 is a deficient number, since it is larger than the sum of its proper divisors (9941747).

166521613 is a wasteful number, since it uses less digits than its factorization.

166521613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8147.

The product of its digits is 6480, while the sum is 31.

The square root of 166521613 is about 12904.3253601263. The cubic root of 166521613 is about 550.1615095922.

The spelling of 166521613 in words is "one hundred sixty-six million, five hundred twenty-one thousand, six hundred thirteen".