261680277 has 4 divisors (see below), whose sum is σ = 348907040. Its totient is φ = 174453516.

The previous prime is 261680261. The next prime is 261680297. The reversal of 261680277 is 772086162.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 261680277 - 2⁴ = 261680261 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261680297) 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, 43613377 + ... + 43613382.

It is an arithmetic number, because the mean of its divisors is an integer number (87226760).

Almost surely, 2^261680277 is an apocalyptic number.

It is an amenable number.

261680277 is a deficient number, since it is larger than the sum of its proper divisors (87226763).

261680277 is an equidigital number, since it uses as much as digits as its factorization.

261680277 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87226762.

The product of its (nonzero) digits is 56448, while the sum is 39.

The square root of 261680277 is about 16176.5347648994. The cubic root of 261680277 is about 639.6223985146.

The spelling of 261680277 in words is "two hundred sixty-one million, six hundred eighty thousand, two hundred seventy-seven".