991920386304 has 81 divisors (see below), whose sum is σ = 2860088851893. Its totient is φ = 330624193536.

The previous prime is 991920386267. The next prime is 991920386333. The reversal of 991920386304 is 403683029199.

The square root of 991920386304 is 995952.

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

991920386304 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 27439259904 + 964481126400 = 165648^2 + 982080^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 47795322 + ... + 47816070.

Almost surely, 2^991920386304 is an apocalyptic number.

991920386304 is the 995952-nd square number.

It is an amenable number.

991920386304 is an abundant number, since it is smaller than the sum of its proper divisors (1868168465589).

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

991920386304 is an frugal number, since it uses more digits than its factorization.

991920386304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41520 (or 20754 counting only the distinct ones).

The product of its (nonzero) digits is 2519424, while the sum is 54.

The spelling of 991920386304 in words is "nine hundred ninety-one billion, nine hundred twenty million, three hundred eighty-six thousand, three hundred four".