261215185 has 16 divisors (see below), whose sum is σ = 390805632. Its totient is φ = 162835200.

The previous prime is 261215167. The next prime is 261215231. The reversal of 261215185 is 581512162.

It is not a de Polignac number, because 261215185 - 2²¹ = 259118033 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 338856 + ... + 339625.

It is an arithmetic number, because the mean of its divisors is an integer number (24425352).

Almost surely, 2^261215185 is an apocalyptic number.

It is an amenable number.

261215185 is a deficient number, since it is larger than the sum of its proper divisors (129590447).

261215185 is a wasteful number, since it uses less digits than its factorization.

261215185 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 678504.

The product of its digits is 4800, while the sum is 31.

The square root of 261215185 is about 16162.1528578343. The cubic root of 261215185 is about 639.2432339349.

The spelling of 261215185 in words is "two hundred sixty-one million, two hundred fifteen thousand, one hundred eighty-five".