261121275 has 72 divisors (see below), whose sum is σ = 521417520. Its totient is φ = 124139520.

The previous prime is 261121253. The next prime is 261121291. The reversal of 261121275 is 572121162.

261121275 is a `hidden beast` number, since 2 + 611 + 21 + 27 + 5 = 666.

It is not a de Polignac number, because 261121275 - 2⁵ = 261121243 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 70879 + ... + 74471.

It is an arithmetic number, because the mean of its divisors is an integer number (7241910).

Almost surely, 2^261121275 is an apocalyptic number.

261121275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

261121275 is a deficient number, since it is larger than the sum of its proper divisors (260296245).

261121275 is a wasteful number, since it uses less digits than its factorization.

261121275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3645 (or 3637 counting only the distinct ones).

The product of its digits is 1680, while the sum is 27.

The square root of 261121275 is about 16159.2473525223. The cubic root of 261121275 is about 639.1666195432.

The spelling of 261121275 in words is "two hundred sixty-one million, one hundred twenty-one thousand, two hundred seventy-five".