399757842 has 192 divisors, whose sum is σ = 1051674624. Its totient is φ = 112674240.

The previous prime is 399757823. The next prime is 399757849. The reversal of 399757842 is 248757993.

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 (399757849) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 8505463 + ... + 8505509.

It is an arithmetic number, because the mean of its divisors is an integer number (5477472).

Almost surely, 2^399757842 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 399757842, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (525837312).

399757842 is an abundant number, since it is smaller than the sum of its proper divisors (651916782).

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

399757842 is a wasteful number, since it uses less digits than its factorization.

399757842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155 (or 143 counting only the distinct ones).

The product of its digits is 3810240, while the sum is 54.

The square root of 399757842 is about 19993.9451334648. The cubic root of 399757842 is about 736.6575834301.

The spelling of 399757842 in words is "three hundred ninety-nine million, seven hundred fifty-seven thousand, eight hundred forty-two".