166985557 has 4 divisors (see below), whose sum is σ = 168606880. Its totient is φ = 165364236.

The previous prime is 166985537. The next prime is 166985587. The reversal of 166985557 is 755589661.

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-166985557 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166985537) 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, 810507 + ... + 810712.

It is an arithmetic number, because the mean of its divisors is an integer number (42151720).

Almost surely, 2^166985557 is an apocalyptic number.

It is an amenable number.

166985557 is a deficient number, since it is larger than the sum of its proper divisors (1621323).

166985557 is a wasteful number, since it uses less digits than its factorization.

166985557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1621322.

The product of its digits is 2268000, while the sum is 52.

The square root of 166985557 is about 12922.2891547899. The cubic root of 166985557 is about 550.6719687628.

The spelling of 166985557 in words is "one hundred sixty-six million, nine hundred eighty-five thousand, five hundred fifty-seven".