399956224 has 36 divisors (see below), whose sum is σ = 800317980. Its totient is φ = 199485440.

The previous prime is 399956191. The next prime is 399956257. The reversal of 399956224 is 422659993.

It is an interprime number because it is at equal distance from previous prime (399956191) and next prime (399956257).

It can be written as a sum of positive squares in 2 ways, for example, as 283316224 + 116640000 = 16832^2 + 10800^2 .

It is a super-2 number, since 2×399956224² = 319929962232676352, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 116322 + ... + 119710.

It is an arithmetic number, because the mean of its divisors is an integer number (22231055).

Almost surely, 2^399956224 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 399956224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (400158990).

399956224 is an abundant number, since it is smaller than the sum of its proper divisors (400361756).

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

399956224 is an equidigital number, since it uses as much as digits as its factorization.

399956224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3866 (or 3852 counting only the distinct ones).

The product of its digits is 1049760, while the sum is 49.

The square root of 399956224 is about 19998.9055700556. The cubic root of 399956224 is about 736.7794200537.

The spelling of 399956224 in words is "three hundred ninety-nine million, nine hundred fifty-six thousand, two hundred twenty-four".