121891990575 has 24 divisors (see below), whose sum is σ = 212134835200. Its totient is φ = 61587531360.

The previous prime is 121891990573. The next prime is 121891990589. The reversal of 121891990575 is 575099198121.

It is not a de Polignac number, because 121891990575 - 2¹ = 121891990573 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121891990573) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 42767695 + ... + 42770544.

Almost surely, 2^121891990575 is an apocalyptic number.

121891990575 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

121891990575 is a deficient number, since it is larger than the sum of its proper divisors (90242844625).

121891990575 is a wasteful number, since it uses less digits than its factorization.

121891990575 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85538271 (or 85538266 counting only the distinct ones).

The product of its (nonzero) digits is 2041200, while the sum is 57.

The spelling of 121891990575 in words is "one hundred twenty-one billion, eight hundred ninety-one million, nine hundred ninety thousand, five hundred seventy-five".