261325166 has 4 divisors (see below), whose sum is σ = 391987752. Its totient is φ = 130662582.

The previous prime is 261325153. The next prime is 261325187. The reversal of 261325166 is 661523162.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65331290 + ... + 65331293.

It is an arithmetic number, because the mean of its divisors is an integer number (97996938).

Almost surely, 2^261325166 is an apocalyptic number.

261325166 is a deficient number, since it is larger than the sum of its proper divisors (130662586).

261325166 is a wasteful number, since it uses less digits than its factorization.

261325166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130662585.

The product of its digits is 12960, while the sum is 32.

The square root of 261325166 is about 16165.5549239734. The cubic root of 261325166 is about 639.3329361543.

The spelling of 261325166 in words is "two hundred sixty-one million, three hundred twenty-five thousand, one hundred sixty-six".