399684541 has 4 divisors (see below), whose sum is σ = 399827584. Its totient is φ = 399541500.

The previous prime is 399684533. The next prime is 399684553. The reversal of 399684541 is 145486993.

It is a happy number.

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: 145486993 = 307 ⋅473899.

It is a cyclic number.

It is not a de Polignac number, because 399684541 - 2³ = 399684533 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 (399684511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67245 + ... + 72946.

It is an arithmetic number, because the mean of its divisors is an integer number (99956896).

Almost surely, 2^399684541 is an apocalyptic number.

It is an amenable number.

399684541 is a deficient number, since it is larger than the sum of its proper divisors (143043).

399684541 is a wasteful number, since it uses less digits than its factorization.

399684541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143042.

The product of its digits is 933120, while the sum is 49.

The square root of 399684541 is about 19992.1119694744. Note that the first 3 decimals coincide. The cubic root of 399684541 is about 736.6125553050.

The spelling of 399684541 in words is "three hundred ninety-nine million, six hundred eighty-four thousand, five hundred forty-one".