399128278756 has 9 divisors (see below), whose sum is σ = 698476699011. Its totient is φ = 199563507612.

The previous prime is 399128278733. The next prime is 399128278771. The reversal of 399128278756 is 657872821993.

The square root of 399128278756 is 631766.

It is a perfect power (a square), and thus also a powerful number.

It is a super-3 number, since 3×399128278756³ (a number of 36 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 399128278691 and 399128278700.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 1105591 + ... + 1421473.

Almost surely, 2^399128278756 is an apocalyptic number.

399128278756 is the 631766-th square number.

It is an amenable number.

399128278756 is a deficient number, since it is larger than the sum of its proper divisors (299348420255).

399128278756 is an frugal number, since it uses more digits than its factorization.

399128278756 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 631770 (or 315885 counting only the distinct ones).

The product of its digits is 91445760, while the sum is 67.

The spelling of 399128278756 in words is "three hundred ninety-nine billion, one hundred twenty-eight million, two hundred seventy-eight thousand, seven hundred fifty-six".