399881099 has 2 divisors, whose sum is σ = 399881100. Its totient is φ = 399881098.

The previous prime is 399881071. The next prime is 399881101. The reversal of 399881099 is 990188993.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 399881099 - 2²⁰ = 398832523 is a prime.

Together with 399881101, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (399887099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199940549 + 199940550.

It is an arithmetic number, because the mean of its divisors is an integer number (199940550).

Almost surely, 2^399881099 is an apocalyptic number.

399881099 is a deficient number, since it is larger than the sum of its proper divisors (1).

399881099 is an equidigital number, since it uses as much as digits as its factorization.

399881099 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1259712, while the sum is 56.

The square root of 399881099 is about 19997.0272540695. The cubic root of 399881099 is about 736.7332866550.

The spelling of 399881099 in words is "three hundred ninety-nine million, eight hundred eighty-one thousand, ninety-nine".