99981491 has 2 divisors, whose sum is σ = 99981492. Its totient is φ = 99981490.

The previous prime is 99981467. The next prime is 99981509. The reversal of 99981491 is 19418999.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 99981491 - 2²⁶ = 32872627 is a prime.

It is not a weakly prime, because it can be changed into another prime (99981421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49990745 + 49990746.

It is an arithmetic number, because the mean of its divisors is an integer number (49990746).

Almost surely, 2^99981491 is an apocalyptic number.

99981491 is a deficient number, since it is larger than the sum of its proper divisors (1).

99981491 is an equidigital number, since it uses as much as digits as its factorization.

99981491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 209952, while the sum is 50.

The square root of 99981491 is about 9999.0745071732. The cubic root of 99981491 is about 464.1302445384.

The spelling of 99981491 in words is "ninety-nine million, nine hundred eighty-one thousand, four hundred ninety-one".