399531097728 has 1152 divisors, whose sum is σ = 1485597360000. Its totient is φ = 106662334464.

The previous prime is 399531097723. The next prime is 399531097741. The reversal of 399531097728 is 827790135993.

399531097728 is a `hidden beast` number, since 3 + 9 + 9 + 531 + 0 + 9 + 77 + 28 = 666.

It is a tau number, because it is divible by the number of its divisors (1152).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (399531097723) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 5473028700 + ... + 5473028772.

Almost surely, 2^399531097728 is an apocalyptic number.

399531097728 is a gapful number since it is divisible by the number (38) 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 399531097728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (742798680000).

399531097728 is an abundant number, since it is smaller than the sum of its proper divisors (1086066262272).

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

399531097728 is an frugal number, since it uses more digits than its factorization.

399531097728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151 (or 104 counting only the distinct ones).

The product of its (nonzero) digits is 25719120, while the sum is 63.

The spelling of 399531097728 in words is "three hundred ninety-nine billion, five hundred thirty-one million, ninety-seven thousand, seven hundred twenty-eight".