261776961 has 32 divisors (see below), whose sum is σ = 415653120. Its totient is φ = 162404352.

The previous prime is 261776953. The next prime is 261776987. The reversal of 261776961 is 169677162.

It is a happy number.

261776961 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 261776961 - 2³ = 261776953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261766961) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 17281 + ... + 28673.

It is an arithmetic number, because the mean of its divisors is an integer number (12989160).

Almost surely, 2^261776961 is an apocalyptic number.

It is an amenable number.

261776961 is a deficient number, since it is larger than the sum of its proper divisors (153876159).

261776961 is a wasteful number, since it uses less digits than its factorization.

261776961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11462 (or 11456 counting only the distinct ones).

The product of its digits is 190512, while the sum is 45.

The square root of 261776961 is about 16179.5228916059. The cubic root of 261776961 is about 639.7011633824.

The spelling of 261776961 in words is "two hundred sixty-one million, seven hundred seventy-six thousand, nine hundred sixty-one".