261152682961 has 27 divisors (see below), whose sum is σ = 272158288873. Its totient is φ = 250589161160.

The previous prime is 261152682943. The next prime is 261152682991. The reversal of 261152682961 is 169286251162.

It is a happy number.

The square root of 261152682961 is 511031.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 261152682961 - 2⁵ = 261152682929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261152682911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1993531866 + ... + 1993531996.

Almost surely, 2^261152682961 is an apocalyptic number.

261152682961 is the 511031-st square number.

261152682961 is the 255516-th centered octagonal number.

It is an amenable number.

261152682961 is a deficient number, since it is larger than the sum of its proper divisors (11005605912).

261152682961 is an frugal number, since it uses more digits than its factorization.

261152682961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 522 (or 261 counting only the distinct ones).

The product of its digits is 622080, while the sum is 49.

Multiplying 261152682961 by its sum of digits (49), we get a square (12796481465089 = 3577217²).

The spelling of 261152682961 in words is "two hundred sixty-one billion, one hundred fifty-two million, six hundred eighty-two thousand, nine hundred sixty-one".