121312656 has 30 divisors (see below), whose sum is σ = 339507350. Its totient is φ = 40437504.

The previous prime is 121312643. The next prime is 121312657. The reversal of 121312656 is 656213121.

121312656 is a `hidden beast` number, since 1 + 2 + 1 + 3 + 1 + 2 + 656 = 666.

It can be written as a sum of positive squares in only one way, i.e., 78854400 + 42458256 = 8880^2 + 6516^2 .

It is not an unprimeable number, because it can be changed into a prime (121312657) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 421081 + ... + 421368.

Almost surely, 2^121312656 is an apocalyptic number.

121312656 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

121312656 is an abundant number, since it is smaller than the sum of its proper divisors (218194694).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

121312656 is a wasteful number, since it uses less digits than its factorization.

121312656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 842463 (or 842454 counting only the distinct ones).

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

The square root of 121312656 is about 11014.2024677232. The cubic root of 121312656 is about 495.0343900196.

Adding to 121312656 its reverse (656213121), we get a palindrome (777525777).

The spelling of 121312656 in words is "one hundred twenty-one million, three hundred twelve thousand, six hundred fifty-six".