399973680 has 320 divisors, whose sum is σ = 1469905920. Its totient is φ = 99753984.

The previous prime is 399973633. The next prime is 399973681. The reversal of 399973680 is 86379993.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (399973681) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4123392 + ... + 4123488.

It is an arithmetic number, because the mean of its divisors is an integer number (4593456).

Almost surely, 2^399973680 is an apocalyptic number.

399973680 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 399973680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (734952960).

399973680 is an abundant number, since it is smaller than the sum of its proper divisors (1069932240).

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

399973680 is a wasteful number, since it uses less digits than its factorization.

399973680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225 (or 213 counting only the distinct ones).

The product of its (nonzero) digits is 2204496, while the sum is 54.

The square root of 399973680 is about 19999.3419891755. The cubic root of 399973680 is about 736.7901387554.

The spelling of 399973680 in words is "three hundred ninety-nine million, nine hundred seventy-three thousand, six hundred eighty".