121010199991 has 2 divisors, whose sum is σ = 121010199992. Its totient is φ = 121010199990.

The previous prime is 121010199983. The next prime is 121010200019. The reversal of 121010199991 is 199991010121.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 121010199991 - 2³ = 121010199983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121010199911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60505099995 + 60505099996.

It is an arithmetic number, because the mean of its divisors is an integer number (60505099996).

Almost surely, 2^121010199991 is an apocalyptic number.

121010199991 is a deficient number, since it is larger than the sum of its proper divisors (1).

121010199991 is an equidigital number, since it uses as much as digits as its factorization.

121010199991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13122, while the sum is 43.

The spelling of 121010199991 in words is "one hundred twenty-one billion, ten million, one hundred ninety-nine thousand, nine hundred ninety-one".