166477721 has 4 divisors (see below), whose sum is σ = 166531200. Its totient is φ = 166424244.

The previous prime is 166477711. The next prime is 166477757. The reversal of 166477721 is 127774661.

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 a de Polignac number, because none of the positive numbers 2^k-166477721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166477711) 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 3 ways as a sum of consecutive naturals, for example, 21761 + ... + 28398.

It is an arithmetic number, because the mean of its divisors is an integer number (41632800).

Almost surely, 2^166477721 is an apocalyptic number.

It is an amenable number.

166477721 is a deficient number, since it is larger than the sum of its proper divisors (53479).

166477721 is an equidigital number, since it uses as much as digits as its factorization.

166477721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53478.

The product of its digits is 98784, while the sum is 41.

The square root of 166477721 is about 12902.6245779686. The cubic root of 166477721 is about 550.1131678976.

The spelling of 166477721 in words is "one hundred sixty-six million, four hundred seventy-seven thousand, seven hundred twenty-one".