991121020121199 has 192 divisors, whose sum is σ = 1514726519685120. Its totient is φ = 575327674521600.

The previous prime is 991121020121033. The next prime is 991121020121201.

991121020121199 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 991121020121199 - 2²⁷ = 991120885903471 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991121020122199) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 903483153619 + ... + 903483154715.

It is an arithmetic number, because the mean of its divisors is an integer number (7889200623360).

Almost surely, 2^{991121020121199} is an apocalyptic number.

991121020121199 is a deficient number, since it is larger than the sum of its proper divisors (523605499563921).

991121020121199 is a wasteful number, since it uses less digits than its factorization.

991121020121199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2542 (or 2531 counting only the distinct ones).

The product of its (nonzero) digits is 52488, while the sum is 48.

The spelling of 991121020121199 in words is "nine hundred ninety-one trillion, one hundred twenty-one billion, twenty million, one hundred twenty-one thousand, one hundred ninety-nine".