991331699 has 2 divisors, whose sum is σ = 991331700. Its totient is φ = 991331698.

The previous prime is 991331687. The next prime is 991331741. The reversal of 991331699 is 996133199.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 991331699 - 2⁴ = 991331683 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (991331899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495665849 + 495665850.

It is an arithmetic number, because the mean of its divisors is an integer number (495665850).

Almost surely, 2^991331699 is an apocalyptic number.

991331699 is a deficient number, since it is larger than the sum of its proper divisors (1).

991331699 is an equidigital number, since it uses as much as digits as its factorization.

991331699 is an evil number, because the sum of its binary digits is even.

The product of its digits is 354294, while the sum is 50.

The square root of 991331699 is about 31485.4204196164. The cubic root of 991331699 is about 997.1021770670.

The spelling of 991331699 in words is "nine hundred ninety-one million, three hundred thirty-one thousand, six hundred ninety-nine".