121391549172 has 36 divisors (see below), whose sum is σ = 314335031556. Its totient is φ = 39476926080.

The previous prime is 121391549107. The next prime is 121391549177. The reversal of 121391549172 is 271945193121.

121391549172 is a `hidden beast` number, since 1 + 2 + 1 + 3 + 91 + 5 + 491 + 72 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 24921673956 + 96469875216 = 157866^2 + 310596^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121391549177) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 41120323 + ... + 41123274.

Almost surely, 2^121391549172 is an apocalyptic number.

121391549172 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

121391549172 is an abundant number, since it is smaller than the sum of its proper divisors (192943482384).

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

121391549172 is a wasteful number, since it uses less digits than its factorization.

121391549172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82243648 (or 82243643 counting only the distinct ones).

The product of its digits is 136080, while the sum is 45.

The spelling of 121391549172 in words is "one hundred twenty-one billion, three hundred ninety-one million, five hundred forty-nine thousand, one hundred seventy-two".