261278377 has 4 divisors (see below), whose sum is σ = 261705220. Its totient is φ = 260851536.

The previous prime is 261278357. The next prime is 261278383. The reversal of 261278377 is 773872162.

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

It can be written as a sum of positive squares in 2 ways, for example, as 746496 + 260531881 = 864^2 + 16141^2 .

It is a cyclic number.

It is not a de Polignac number, because 261278377 - 2⁷ = 261278249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261278357) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 212502 + ... + 213727.

It is an arithmetic number, because the mean of its divisors is an integer number (65426305).

Almost surely, 2^261278377 is an apocalyptic number.

It is an amenable number.

261278377 is a deficient number, since it is larger than the sum of its proper divisors (426843).

261278377 is an equidigital number, since it uses as much as digits as its factorization.

261278377 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 426842.

The product of its digits is 197568, while the sum is 43.

The square root of 261278377 is about 16164.1076771964. The cubic root of 261278377 is about 639.2947773926.

The spelling of 261278377 in words is "two hundred sixty-one million, two hundred seventy-eight thousand, three hundred seventy-seven".