261383591 has 12 divisors (see below), whose sum is σ = 310530528. Its totient is φ = 219274272.

The previous prime is 261383543. The next prime is 261383593. The reversal of 261383591 is 195383162.

It is a happy number.

It is not a de Polignac number, because 261383591 - 2¹⁸ = 261121447 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261383593) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 54446 + ... + 59051.

It is an arithmetic number, because the mean of its divisors is an integer number (25877544).

Almost surely, 2^261383591 is an apocalyptic number.

261383591 is a deficient number, since it is larger than the sum of its proper divisors (49146937).

261383591 is a wasteful number, since it uses less digits than its factorization.

261383591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113558 (or 113551 counting only the distinct ones).

The product of its digits is 38880, while the sum is 38.

The square root of 261383591 is about 16167.3619060130. The cubic root of 261383591 is about 639.3805782599.

The spelling of 261383591 in words is "two hundred sixty-one million, three hundred eighty-three thousand, five hundred ninety-one".