166640625 has 64 divisors (see below), whose sum is σ = 312499200. Its totient is φ = 87750000.

The previous prime is 166640611. The next prime is 166640651. The reversal of 166640625 is 526046661.

It is a happy number.

It is not a de Polignac number, because 166640625 - 2⁶ = 166640561 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 166640625.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2109336 + ... + 2109414.

It is an arithmetic number, because the mean of its divisors is an integer number (4882800).

Almost surely, 2^166640625 is an apocalyptic number.

166640625 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

166640625 is a deficient number, since it is larger than the sum of its proper divisors (145858575).

166640625 is an frugal number, since it uses more digits than its factorization.

166640625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123 (or 87 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 166640625 is about 12908.9358585439. The cubic root of 166640625 is about 550.2925440932.

The spelling of 166640625 in words is "one hundred sixty-six million, six hundred forty thousand, six hundred twenty-five".