399680881 has 4 divisors (see below), whose sum is σ = 399999600. Its totient is φ = 399362164.

The previous prime is 399680857. The next prime is 399680909. The reversal of 399680881 is 188086993.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 188086993 = 89 ⋅2113337.

It is a cyclic number.

It is not a de Polignac number, because 399680881 - 2¹¹ = 399678833 is a prime.

It is a super-2 number, since 2×399680881² = 319489613273872322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399680851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 157471 + ... + 159988.

It is an arithmetic number, because the mean of its divisors is an integer number (99999900).

Almost surely, 2^399680881 is an apocalyptic number.

It is an amenable number.

399680881 is a deficient number, since it is larger than the sum of its proper divisors (318719).

399680881 is a wasteful number, since it uses less digits than its factorization.

399680881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 318718.

The product of its (nonzero) digits is 746496, while the sum is 52.

The square root of 399680881 is about 19992.0204331628. The cubic root of 399680881 is about 736.6103068567.

The spelling of 399680881 in words is "three hundred ninety-nine million, six hundred eighty thousand, eight hundred eighty-one".