399361643 has 4 divisors (see below), whose sum is σ = 399743400. Its totient is φ = 398979888.

The previous prime is 399361621. The next prime is 399361649. The reversal of 399361643 is 346163993.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 346163993 = 7 ⋅49451999.

It is a cyclic number.

It is not a de Polignac number, because 399361643 - 2¹⁸ = 399099499 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 399361594 and 399361603.

It is not an unprimeable number, because it can be changed into a prime (399361649) 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, 189305 + ... + 191402.

It is an arithmetic number, because the mean of its divisors is an integer number (99935850).

Almost surely, 2^399361643 is an apocalyptic number.

399361643 is a deficient number, since it is larger than the sum of its proper divisors (381757).

399361643 is a wasteful number, since it uses less digits than its factorization.

399361643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 381756.

The product of its digits is 314928, while the sum is 44.

The square root of 399361643 is about 19984.0347027321. The cubic root of 399361643 is about 736.4141364880.

It can be divided in two parts, 399361 and 643, that added together give a palindrome (400004).

The spelling of 399361643 in words is "three hundred ninety-nine million, three hundred sixty-one thousand, six hundred forty-three".