12169138891921 has 6 divisors (see below), whose sum is σ = 13375995641666. Its totient is φ = 11062853538000.

The previous prime is 12169138891913. The next prime is 12169138891939. The reversal of 12169138891921 is 12919883196121.

It can be written as a sum of positive squares in only one way, i.e., 11532272646400 + 636866245521 = 3395920^2 + 798039^2 .

It is not a de Polignac number, because 12169138891921 - 2³ = 12169138891913 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 12169138891921.

It is not an unprimeable number, because it can be changed into a prime (12169138891961) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 50285697780 + ... + 50285698021.

Almost surely, 2^{12169138891921} is an apocalyptic number.

12169138891921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12169138891921 is a deficient number, since it is larger than the sum of its proper divisors (1206856749745).

12169138891921 is a wasteful number, since it uses less digits than its factorization.

12169138891921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100571395823 (or 100571395812 counting only the distinct ones).

The product of its digits is 3359232, while the sum is 61.

The spelling of 12169138891921 in words is "twelve trillion, one hundred sixty-nine billion, one hundred thirty-eight million, eight hundred ninety-one thousand, nine hundred twenty-one".