399420 has 72 divisors (see below), whose sum is σ = 1389024. Its totient is φ = 91008.

The previous prime is 399409. The next prime is 399433. The reversal of 399420 is 24993.

It is a zygodrome in base 2.

It is a congruent number.

It is an unprimeable number.

399420 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1102 + ... + 1418.

It is an arithmetic number, because the mean of its divisors is an integer number (19292).

2³⁹⁹⁴²⁰ is an apocalyptic number.

399420 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 399420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (694512).

399420 is an abundant number, since it is smaller than the sum of its proper divisors (989604).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

399420 is a wasteful number, since it uses less digits than its factorization.

399420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 339 (or 334 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 27.

The square root of 399420 is about 631.9968354351. The cubic root of 399420 is about 73.6450004418.

The spelling of 399420 in words is "three hundred ninety-nine thousand, four hundred twenty".