261577231 has 4 divisors (see below), whose sum is σ = 267142752. Its totient is φ = 256011712.

The previous prime is 261577223. The next prime is 261577273. The reversal of 261577231 is 132775162.

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

It is a cyclic number.

It is not a de Polignac number, because 261577231 - 2³ = 261577223 is a prime.

It is a super-2 number, since 2×261577231² = 136845295555254722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261577291) by changing a digit.

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, 2782690 + ... + 2782783.

It is an arithmetic number, because the mean of its divisors is an integer number (66785688).

Almost surely, 2^261577231 is an apocalyptic number.

261577231 is a deficient number, since it is larger than the sum of its proper divisors (5565521).

261577231 is an equidigital number, since it uses as much as digits as its factorization.

261577231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5565520.

The product of its digits is 17640, while the sum is 34.

The square root of 261577231 is about 16173.3494057354. The cubic root of 261577231 is about 639.5384294005.

The spelling of 261577231 in words is "two hundred sixty-one million, five hundred seventy-seven thousand, two hundred thirty-one".