261657078 has 16 divisors (see below), whose sum is σ = 533188656. Its totient is φ = 85573280.

The previous prime is 261657059. The next prime is 261657089. The reversal of 261657078 is 870756162.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 411093 + ... + 411728.

It is an arithmetic number, because the mean of its divisors is an integer number (33324291).

Almost surely, 2^261657078 is an apocalyptic number.

261657078 is an abundant number, since it is smaller than the sum of its proper divisors (271531578).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261657078 is a wasteful number, since it uses less digits than its factorization.

261657078 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 822879.

The product of its (nonzero) digits is 141120, while the sum is 42.

The square root of 261657078 is about 16175.8176918510. The cubic root of 261657078 is about 639.6034962639.

The spelling of 261657078 in words is "two hundred sixty-one million, six hundred fifty-seven thousand, seventy-eight".