121099999981 has 2 divisors, whose sum is σ = 121099999982. Its totient is φ = 121099999980.

The previous prime is 121099999907. The next prime is 121100000051. The reversal of 121099999981 is 189999990121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 98758719081 + 22341280900 = 314259^2 + 149470^2 .

It is a cyclic number.

It is not a de Polignac number, because 121099999981 - 2²³ = 121091611373 is a prime.

It is a super-2 number, since 2×121099999981² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121099939981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60549999990 + 60549999991.

It is an arithmetic number, because the mean of its divisors is an integer number (60549999991).

Almost surely, 2^121099999981 is an apocalyptic number.

It is an amenable number.

121099999981 is a deficient number, since it is larger than the sum of its proper divisors (1).

121099999981 is an equidigital number, since it uses as much as digits as its factorization.

121099999981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8503056, while the sum is 67.

The spelling of 121099999981 in words is "one hundred twenty-one billion, ninety-nine million, nine hundred ninety-nine thousand, nine hundred eighty-one".