261575640 has 48 divisors (see below), whose sum is σ = 850122000. Its totient is φ = 69753408.

The previous prime is 261575623. The next prime is 261575647. The reversal of 261575640 is 46575162.

It is a happy number.

261575640 is a `hidden beast` number, since 2 + 6 + 1 + 5 + 7 + 5 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 261575595 and 261575604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261575647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 362940 + ... + 363659.

It is an arithmetic number, because the mean of its divisors is an integer number (17710875).

Almost surely, 2^261575640 is an apocalyptic number.

261575640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261575640 is an abundant number, since it is smaller than the sum of its proper divisors (588546360).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261575640 is a wasteful number, since it uses less digits than its factorization.

261575640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 726616 (or 726609 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The square root of 261575640 is about 16173.3002198067. The cubic root of 261575640 is about 639.5371327691.

The spelling of 261575640 in words is "two hundred sixty-one million, five hundred seventy-five thousand, six hundred forty".