991916402500 has 45 divisors (see below), whose sum is σ = 2169231691627. Its totient is φ = 396746642000.

The previous prime is 991916402473. The next prime is 991916402567. The reversal of 991916402500 is 5204619199.

It is a happy number.

The square root of 991916402500 is 995950.

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

It can be written as a sum of positive squares in 2 ways, for example, as 77766245956 + 914150156544 = 278866^2 + 956112^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 49787541 + ... + 49807459.

Almost surely, 2^991916402500 is an apocalyptic number.

991916402500 is the 995950-th square number.

It is an amenable number.

991916402500 is an abundant number, since it is smaller than the sum of its proper divisors (1177315289127).

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

991916402500 is an frugal number, since it uses more digits than its factorization.

991916402500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39862 (or 19926 counting only the distinct ones).

The product of its (nonzero) digits is 174960, while the sum is 46.

The spelling of 991916402500 in words is "nine hundred ninety-one billion, nine hundred sixteen million, four hundred two thousand, five hundred".