166528832721 has 4 divisors (see below), whose sum is σ = 222038443632. Its totient is φ = 111019221812.

The previous prime is 166528832683. The next prime is 166528832737. The reversal of 166528832721 is 127238825661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 166528832721 - 2⁷ = 166528832593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (166528832791) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27754805451 + ... + 27754805456.

It is an arithmetic number, because the mean of its divisors is an integer number (55509610908).

Almost surely, 2^166528832721 is an apocalyptic number.

It is an amenable number.

166528832721 is a deficient number, since it is larger than the sum of its proper divisors (55509610911).

166528832721 is an equidigital number, since it uses as much as digits as its factorization.

166528832721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55509610910.

The product of its digits is 1935360, while the sum is 51.

The spelling of 166528832721 in words is "one hundred sixty-six billion, five hundred twenty-eight million, eight hundred thirty-two thousand, seven hundred twenty-one".