399245947991 has 4 divisors (see below), whose sum is σ = 435541034184. Its totient is φ = 362950861800.

The previous prime is 399245947987. The next prime is 399245947993. The reversal of 399245947991 is 199749542993.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 399245947991 - 2² = 399245947987 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399245947993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18147543080 + ... + 18147543101.

It is an arithmetic number, because the mean of its divisors is an integer number (108885258546).

Almost surely, 2^399245947991 is an apocalyptic number.

399245947991 is a deficient number, since it is larger than the sum of its proper divisors (36295086193).

399245947991 is a wasteful number, since it uses less digits than its factorization.

399245947991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36295086192.

The product of its digits is 198404640, while the sum is 71.

The spelling of 399245947991 in words is "three hundred ninety-nine billion, two hundred forty-five million, nine hundred forty-seven thousand, nine hundred ninety-one".