166513621 has 8 divisors (see below), whose sum is σ = 175921920. Its totient is φ = 157349808.

The previous prime is 166513619. The next prime is 166513639. The reversal of 166513621 is 126315661.

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 166513621 - 2¹ = 166513619 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166513601) 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, 59721 + ... + 62446.

It is an arithmetic number, because the mean of its divisors is an integer number (21990240).

Almost surely, 2^166513621 is an apocalyptic number.

It is an amenable number.

166513621 is a deficient number, since it is larger than the sum of its proper divisors (9408299).

166513621 is a wasteful number, since it uses less digits than its factorization.

166513621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122243.

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

The square root of 166513621 is about 12904.0156927989. The cubic root of 166513621 is about 550.1527080098.

The spelling of 166513621 in words is "one hundred sixty-six million, five hundred thirteen thousand, six hundred twenty-one".