261640275 has 48 divisors (see below), whose sum is σ = 469240800. Its totient is φ = 127872000.

The previous prime is 261640259. The next prime is 261640289. The reversal of 261640275 is 572046162.

It is not a de Polignac number, because 261640275 - 2⁴ = 261640259 is a prime.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 144375 + ... + 146175.

It is an arithmetic number, because the mean of its divisors is an integer number (9775850).

Almost surely, 2^261640275 is an apocalyptic number.

261640275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

261640275 is a deficient number, since it is larger than the sum of its proper divisors (207600525).

261640275 is a wasteful number, since it uses less digits than its factorization.

261640275 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1976 (or 1971 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 33.

The square root of 261640275 is about 16175.2982970949. The cubic root of 261640275 is about 639.5898046952.

The spelling of 261640275 in words is "two hundred sixty-one million, six hundred forty thousand, two hundred seventy-five".