261553775 has 24 divisors (see below), whose sum is σ = 371997024. Its totient is φ = 178704000.

The previous prime is 261553759. The next prime is 261553819. The reversal of 261553775 is 577355162.

It is not a de Polignac number, because 261553775 - 2⁴ = 261553759 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 48725 + ... + 53825.

It is an arithmetic number, because the mean of its divisors is an integer number (15499876).

Almost surely, 2^261553775 is an apocalyptic number.

261553775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

261553775 is a deficient number, since it is larger than the sum of its proper divisors (110443249).

261553775 is a wasteful number, since it uses less digits than its factorization.

261553775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5411 (or 5406 counting only the distinct ones).

The product of its digits is 220500, while the sum is 41.

The square root of 261553775 is about 16172.6242459287. The cubic root of 261553775 is about 639.5193127241.

The spelling of 261553775 in words is "two hundred sixty-one million, five hundred fifty-three thousand, seven hundred seventy-five".