121635261 has 24 divisors (see below), whose sum is σ = 196131936. Its totient is φ = 72001440.

The previous prime is 121635253. The next prime is 121635263. The reversal of 121635261 is 162536121.

121635261 is a `hidden beast` number, since 1 + 2 + 1 + 635 + 26 + 1 = 666.

It is not a de Polignac number, because 121635261 - 2³ = 121635253 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121635263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10030 + ... + 18543.

It is an arithmetic number, because the mean of its divisors is an integer number (8172164).

Almost surely, 2^121635261 is an apocalyptic number.

121635261 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

121635261 is a deficient number, since it is larger than the sum of its proper divisors (74496675).

121635261 is a wasteful number, since it uses less digits than its factorization.

121635261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28633 (or 28630 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 121635261 is about 11028.8376994133. The cubic root of 121635261 is about 495.4728142267.

It can be divided in two parts, 12163 and 5261, that added together give a square (17424 = 132²).

The spelling of 121635261 in words is "one hundred twenty-one million, six hundred thirty-five thousand, two hundred sixty-one".