166509425 has 6 divisors (see below), whose sum is σ = 206471718. Its totient is φ = 133207520.

The previous prime is 166509403. The next prime is 166509439. The reversal of 166509425 is 524905661.

It can be written as a sum of positive squares in 3 ways, for example, as 16128256 + 150381169 = 4016^2 + 12263^2 .

It is a de Polignac number, because none of the positive numbers 2^k-166509425 is a prime.

It is a super-2 number, since 2×166509425² = 55450777227661250, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 3330164 + ... + 3330213.

It is an arithmetic number, because the mean of its divisors is an integer number (34411953).

Almost surely, 2^166509425 is an apocalyptic number.

It is an amenable number.

166509425 is a deficient number, since it is larger than the sum of its proper divisors (39962293).

166509425 is an equidigital number, since it uses as much as digits as its factorization.

166509425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6660387 (or 6660382 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 38.

The square root of 166509425 is about 12903.8531067275. The cubic root of 166509425 is about 550.1480868460.

The spelling of 166509425 in words is "one hundred sixty-six million, five hundred nine thousand, four hundred twenty-five".