399549 has 4 divisors (see below), whose sum is σ = 532736. Its totient is φ = 266364.

The previous prime is 399541. The next prime is 399557. The reversal of 399549 is 945993.

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.

It is an interprime number because it is at equal distance from previous prime (399541) and next prime (399557).

It is not a de Polignac number, because 399549 - 2³ = 399541 is a prime.

It is a D-number.

It is a Duffinian number.

399549 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399541) 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, 66589 + ... + 66594.

It is an arithmetic number, because the mean of its divisors is an integer number (133184).

2³⁹⁹⁵⁴⁹ is an apocalyptic number.

It is an amenable number.

399549 is a deficient number, since it is larger than the sum of its proper divisors (133187).

399549 is a wasteful number, since it uses less digits than its factorization.

399549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133186.

The product of its digits is 43740, while the sum is 39.

The square root of 399549 is about 632.0988846692. The cubic root of 399549 is about 73.6529279221.

The spelling of 399549 in words is "three hundred ninety-nine thousand, five hundred forty-nine".