261401818833 has 24 divisors (see below), whose sum is σ = 394689559680. Its totient is φ = 166397985600.

The previous prime is 261401818819. The next prime is 261401818883. The reversal of 261401818833 is 338818104162.

261401818833 is a `hidden beast` number, since 2 + 61 + 401 + 8 + 188 + 3 + 3 = 666.

It is not a de Polignac number, because 261401818833 - 2³² = 257106851537 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (261401818883) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 991893 + ... + 1227458.

It is an arithmetic number, because the mean of its divisors is an integer number (16445398320).

Almost surely, 2^261401818833 is an apocalyptic number.

261401818833 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

261401818833 is a deficient number, since it is larger than the sum of its proper divisors (133287740847).

261401818833 is a wasteful number, since it uses less digits than its factorization.

261401818833 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2219949 (or 2219946 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 45.

The spelling of 261401818833 in words is "two hundred sixty-one billion, four hundred one million, eight hundred eighteen thousand, eight hundred thirty-three".