12121991436 has 24 divisors (see below), whose sum is σ = 28384600384. Its totient is φ = 4026384720.

The previous prime is 12121991419. The next prime is 12121991443. The reversal of 12121991436 is 63419912121.

It is a junction number, because it is equal to n+sod(n) for n = 12121991394 and 12121991403.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1781350 + ... + 1788141.

Almost surely, 2^12121991436 is an apocalyptic number.

It is an amenable number.

12121991436 is an abundant number, since it is smaller than the sum of its proper divisors (16262608948).

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

12121991436 is a wasteful number, since it uses less digits than its factorization.

12121991436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3569781 (or 3569779 counting only the distinct ones).

The product of its digits is 23328, while the sum is 39.

The spelling of 12121991436 in words is "twelve billion, one hundred twenty-one million, nine hundred ninety-one thousand, four hundred thirty-six".