99121931 has 2 divisors, whose sum is σ = 99121932. Its totient is φ = 99121930.

The previous prime is 99121909. The next prime is 99121937. The reversal of 99121931 is 13912199.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 99121931 - 2¹⁴ = 99105547 is a prime.

It is a super-2 number, since 2×99121931² = 19650314410337522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 99121891 and 99121900.

It is not a weakly prime, because it can be changed into another prime (99121937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49560965 + 49560966.

It is an arithmetic number, because the mean of its divisors is an integer number (49560966).

Almost surely, 2^99121931 is an apocalyptic number.

99121931 is a deficient number, since it is larger than the sum of its proper divisors (1).

99121931 is an equidigital number, since it uses as much as digits as its factorization.

99121931 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4374, while the sum is 35.

The square root of 99121931 is about 9955.9997488951. Note that the first 3 decimals coincide. The cubic root of 99121931 is about 462.7963424403.

It can be divided in two parts, 991 and 21931, that added together give a palindrome (22922).

The spelling of 99121931 in words is "ninety-nine million, one hundred twenty-one thousand, nine hundred thirty-one".