399621 has 8 divisors (see below), whose sum is σ = 550144. Its totient is φ = 257760.

The previous prime is 399617. The next prime is 399643. The reversal of 399621 is 126993.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 399621 - 2² = 399617 is a prime.

It is a Duffinian number.

399621 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2056 + ... + 2241.

It is an arithmetic number, because the mean of its divisors is an integer number (68768).

2³⁹⁹⁶²¹ is an apocalyptic number.

399621 is a gapful number since it is divisible by the number (31) formed by its first and last digit.

It is an amenable number.

399621 is a deficient number, since it is larger than the sum of its proper divisors (150523).

399621 is a wasteful number, since it uses less digits than its factorization.

399621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4331.

The product of its digits is 2916, while the sum is 30.

The square root of 399621 is about 632.1558352179. The cubic root of 399621 is about 73.6573518203.

The spelling of 399621 in words is "three hundred ninety-nine thousand, six hundred twenty-one".