991784941456 has 15 divisors (see below), whose sum is σ = 1921591042203. Its totient is φ = 495890478960.

The previous prime is 991784941451. The next prime is 991784941471. The reversal of 991784941456 is 654149487199.

The square root of 991784941456 is 995884.

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

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 991784941391 and 991784941400.

It is not an unprimeable number, because it can be changed into a prime (991784941451) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 3859051 + ... + 4108021.

Almost surely, 2^991784941456 is an apocalyptic number.

991784941456 is the 995884-th square number.

It is an amenable number.

991784941456 is a deficient number, since it is larger than the sum of its proper divisors (929806100747).

991784941456 is an frugal number, since it uses more digits than its factorization.

991784941456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 497950 (or 248973 counting only the distinct ones).

The product of its digits is 78382080, while the sum is 67.

The spelling of 991784941456 in words is "nine hundred ninety-one billion, seven hundred eighty-four million, nine hundred forty-one thousand, four hundred fifty-six".