261770155 has 4 divisors (see below), whose sum is σ = 314124192. Its totient is φ = 209416120.

The previous prime is 261770123. The next prime is 261770161. The reversal of 261770155 is 551077162.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 261770155 - 2⁵ = 261770123 is a prime.

It is a super-2 number, since 2×261770155² = 137047228097448050, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261770155.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26177011 + ... + 26177020.

It is an arithmetic number, because the mean of its divisors is an integer number (78531048).

Almost surely, 2^261770155 is an apocalyptic number.

261770155 is a deficient number, since it is larger than the sum of its proper divisors (52354037).

261770155 is an equidigital number, since it uses as much as digits as its factorization.

261770155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52354036.

The product of its (nonzero) digits is 14700, while the sum is 34.

The square root of 261770155 is about 16179.3125626523. The cubic root of 261770155 is about 639.6956194213.

The spelling of 261770155 in words is "two hundred sixty-one million, seven hundred seventy thousand, one hundred fifty-five".