261520166 has 8 divisors (see below), whose sum is σ = 409335984. Its totient is φ = 125074840.

The previous prime is 261520159. The next prime is 261520169. The reversal of 261520166 is 661025162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261520169) 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, 2842565 + ... + 2842656.

It is an arithmetic number, because the mean of its divisors is an integer number (51166998).

Almost surely, 2^261520166 is an apocalyptic number.

261520166 is a deficient number, since it is larger than the sum of its proper divisors (147815818).

261520166 is a wasteful number, since it uses less digits than its factorization.

261520166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5685246.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 261520166 is about 16171.5851418468. The cubic root of 261520166 is about 639.4919193448.

The spelling of 261520166 in words is "two hundred sixty-one million, five hundred twenty thousand, one hundred sixty-six".