261608139 has 24 divisors (see below), whose sum is σ = 408913232. Its totient is φ = 160211520.

The previous prime is 261608117. The next prime is 261608143. The reversal of 261608139 is 931806162.

261608139 is a `hidden beast` number, since 2 + 616 + 0 + 8 + 1 + 39 = 666.

It is not a de Polignac number, because 261608139 - 2¹¹ = 261606091 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (261608239) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19389 + ... + 29985.

Almost surely, 2^261608139 is an apocalyptic number.

261608139 is a deficient number, since it is larger than the sum of its proper divisors (147305093).

261608139 is a wasteful number, since it uses less digits than its factorization.

261608139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10827 (or 10824 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 261608139 is about 16174.3049000568. The cubic root of 261608139 is about 639.5636177234.

It can be divided in two parts, 261 and 608139, that added together give a square (608400 = 780²).

The spelling of 261608139 in words is "two hundred sixty-one million, six hundred eight thousand, one hundred thirty-nine".