12121891637 has 8 divisors (see below), whose sum is σ = 12221609400. Its totient is φ = 12022534080.

The previous prime is 12121891619. The next prime is 12121891673. The reversal of 12121891637 is 73619812121.

It can be written as a sum of positive squares in 4 ways, for example, as 535737316 + 11586154321 = 23146^2 + 107639^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12121891637 - 2⁸ = 12121891381 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12121891594 and 12121891603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12121897637) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22262 + ... + 157287.

It is an arithmetic number, because the mean of its divisors is an integer number (1527701175).

Almost surely, 2^12121891637 is an apocalyptic number.

It is an amenable number.

12121891637 is a deficient number, since it is larger than the sum of its proper divisors (99717763).

12121891637 is a wasteful number, since it uses less digits than its factorization.

12121891637 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180103.

The product of its digits is 36288, while the sum is 41.

The spelling of 12121891637 in words is "twelve billion, one hundred twenty-one million, eight hundred ninety-one thousand, six hundred thirty-seven".