261381155 has 16 divisors (see below), whose sum is σ = 359976960. Its totient is φ = 178477152.

The previous prime is 261381149. The next prime is 261381161. The reversal of 261381155 is 551183162.

261381155 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (261381149) and next prime (261381161).

It is not a de Polignac number, because 261381155 - 2⁴ = 261381139 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, 7259 + ... + 23988.

It is an arithmetic number, because the mean of its divisors is an integer number (22498560).

Almost surely, 2^261381155 is an apocalyptic number.

261381155 is a deficient number, since it is larger than the sum of its proper divisors (98595805).

261381155 is a wasteful number, since it uses less digits than its factorization.

261381155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31498.

The product of its digits is 7200, while the sum is 32.

The square root of 261381155 is about 16167.2865688711. The cubic root of 261381155 is about 639.3785919889.

The spelling of 261381155 in words is "two hundred sixty-one million, three hundred eighty-one thousand, one hundred fifty-five".