261686238 has 16 divisors (see below), whose sum is σ = 570951936. Its totient is φ = 79298840.

The previous prime is 261686213. The next prime is 261686251. The reversal of 261686238 is 832686162.

It is a self number, because there is not a number n which added to its sum of digits gives 261686238.

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, 1982406 + ... + 1982537.

It is an arithmetic number, because the mean of its divisors is an integer number (35684496).

Almost surely, 2^261686238 is an apocalyptic number.

261686238 is an abundant number, since it is smaller than the sum of its proper divisors (309265698).

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

261686238 is a wasteful number, since it uses less digits than its factorization.

261686238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3964959.

The product of its digits is 165888, while the sum is 42.

The square root of 261686238 is about 16176.7190122101. The cubic root of 261686238 is about 639.6272552813.

The spelling of 261686238 in words is "two hundred sixty-one million, six hundred eighty-six thousand, two hundred thirty-eight".