261875649 has 12 divisors (see below), whose sum is σ = 406174704. Its totient is φ = 149643144.

The previous prime is 261875639. The next prime is 261875659. The reversal of 261875649 is 946578162.

It is an interprime number because it is at equal distance from previous prime (261875639) and next prime (261875659).

It is not a de Polignac number, because 261875649 - 2⁵ = 261875617 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 261875598 and 261875607.

It is not an unprimeable number, because it can be changed into a prime (261875629) 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, 890587 + ... + 890880.

It is an arithmetic number, because the mean of its divisors is an integer number (33847892).

Almost surely, 2^261875649 is an apocalyptic number.

It is an amenable number.

261875649 is a deficient number, since it is larger than the sum of its proper divisors (144299055).

261875649 is a wasteful number, since it uses less digits than its factorization.

261875649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1781484 (or 1781477 counting only the distinct ones).

The product of its digits is 725760, while the sum is 48.

The square root of 261875649 is about 16182.5723851309. The cubic root of 261875649 is about 639.7815408362.

The spelling of 261875649 in words is "two hundred sixty-one million, eight hundred seventy-five thousand, six hundred forty-nine".