261581245 has 8 divisors (see below), whose sum is σ = 317871360. Its totient is φ = 206615760.

The previous prime is 261581239. The next prime is 261581263. The reversal of 261581245 is 542185162.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 261581245 - 2²³ = 253192637 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261581245.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 330721 + ... + 331510.

It is an arithmetic number, because the mean of its divisors is an integer number (39733920).

Almost surely, 2^261581245 is an apocalyptic number.

It is an amenable number.

261581245 is a deficient number, since it is larger than the sum of its proper divisors (56290115).

261581245 is an equidigital number, since it uses as much as digits as its factorization.

261581245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 662315.

The product of its digits is 19200, while the sum is 34.

The square root of 261581245 is about 16173.4734982934. The cubic root of 261581245 is about 639.5417007022.

The spelling of 261581245 in words is "two hundred sixty-one million, five hundred eighty-one thousand, two hundred forty-five".