261251657 has 8 divisors (see below), whose sum is σ = 265011840. Its totient is φ = 257502960.

The previous prime is 261251651. The next prime is 261251677. The reversal of 261251657 is 756152162.

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

It is a cyclic number.

It is not a de Polignac number, because 261251657 - 2¹² = 261247561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261251651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49718 + ... + 54720.

It is an arithmetic number, because the mean of its divisors is an integer number (33126480).

Almost surely, 2^261251657 is an apocalyptic number.

It is an amenable number.

261251657 is a deficient number, since it is larger than the sum of its proper divisors (3760183).

261251657 is an equidigital number, since it uses as much as digits as its factorization.

261251657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5743.

The product of its digits is 25200, while the sum is 35.

The square root of 261251657 is about 16163.2811334828. The cubic root of 261251657 is about 639.2729838570.

The spelling of 261251657 in words is "two hundred sixty-one million, two hundred fifty-one thousand, six hundred fifty-seven".