399970 has 32 divisors (see below), whose sum is σ = 787968. Its totient is φ = 145728.

The previous prime is 399953. The next prime is 399979. The reversal of 399970 is 79993.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399979) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8487 + ... + 8533.

It is an arithmetic number, because the mean of its divisors is an integer number (24624).

2³⁹⁹⁹⁷⁰ is an apocalyptic number.

399970 is a deficient number, since it is larger than the sum of its proper divisors (387998).

399970 is a wasteful number, since it uses less digits than its factorization.

399970 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114.

The product of its (nonzero) digits is 15309, while the sum is 37.

The square root of 399970 is about 632.4318145065. The cubic root of 399970 is about 73.6787879110.

It can be divided in two parts, 399 and 970, that added together give a square (1369 = 37²).

The spelling of 399970 in words is "three hundred ninety-nine thousand, nine hundred seventy".