121891636 has 12 divisors (see below), whose sum is σ = 213558660. Its totient is φ = 60874880.

The previous prime is 121891621. The next prime is 121891639. The reversal of 121891636 is 636198121.

It can be written as a sum of positive squares in 2 ways, for example, as 6200100 + 115691536 = 2490^2 + 10756^2 .

It is a junction number, because it is equal to n+sod(n) for n = 121891595 and 121891604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121891639) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13771 + ... + 20818.

It is an arithmetic number, because the mean of its divisors is an integer number (17796555).

Almost surely, 2^121891636 is an apocalyptic number.

It is an amenable number.

121891636 is a deficient number, since it is larger than the sum of its proper divisors (91667024).

121891636 is a wasteful number, since it uses less digits than its factorization.

121891636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35474 (or 35472 counting only the distinct ones).

The product of its digits is 15552, while the sum is 37.

The square root of 121891636 is about 11040.4545196292. The cubic root of 121891636 is about 495.8206785431.

The spelling of 121891636 in words is "one hundred twenty-one million, eight hundred ninety-one thousand, six hundred thirty-six".