399957791687 has 2 divisors, whose sum is σ = 399957791688. Its totient is φ = 399957791686.

The previous prime is 399957791677. The next prime is 399957791713. The reversal of 399957791687 is 786197759993.

It is a weak prime.

It is an emirp because it is prime and its reverse (786197759993) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 399957791687 - 2²⁰ = 399956743111 is a prime.

It is a super-2 number, since 2×399957791687² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (399957791627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199978895843 + 199978895844.

It is an arithmetic number, because the mean of its divisors is an integer number (199978895844).

Almost surely, 2^399957791687 is an apocalyptic number.

399957791687 is a deficient number, since it is larger than the sum of its proper divisors (1).

399957791687 is an equidigital number, since it uses as much as digits as its factorization.

399957791687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1620304560, while the sum is 80.

The spelling of 399957791687 in words is "three hundred ninety-nine billion, nine hundred fifty-seven million, seven hundred ninety-one thousand, six hundred eighty-seven".