261932581 has 2 divisors, whose sum is σ = 261932582. Its totient is φ = 261932580.

The previous prime is 261932557. The next prime is 261932621. The reversal of 261932581 is 185239162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 190191681 + 71740900 = 13791^2 + 8470^2 .

It is a cyclic number.

It is not a de Polignac number, because 261932581 - 2⁷ = 261932453 is a prime.

It is a super-2 number, since 2×261932581² = 137217353978643122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 261932581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261935581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130966290 + 130966291.

It is an arithmetic number, because the mean of its divisors is an integer number (130966291).

Almost surely, 2^261932581 is an apocalyptic number.

It is an amenable number.

261932581 is a deficient number, since it is larger than the sum of its proper divisors (1).

261932581 is an equidigital number, since it uses as much as digits as its factorization.

261932581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25920, while the sum is 37.

The square root of 261932581 is about 16184.3313423817. The cubic root of 261932581 is about 639.8279005030.

The spelling of 261932581 in words is "two hundred sixty-one million, nine hundred thirty-two thousand, five hundred eighty-one".