991555344 has 200 divisors, whose sum is σ = 3116180760. Its totient is φ = 302579712.

The previous prime is 991555343. The next prime is 991555441. The reversal of 991555344 is 443555199.

991555344 is a `hidden beast` number, since 9 + 91 + 5 + 553 + 4 + 4 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 498182400 + 493372944 = 22320^2 + 22212^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 991555344.

It is not an unprimeable number, because it can be changed into a prime (991555343) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 3858064 + ... + 3858320.

Almost surely, 2^991555344 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991555344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1558090380).

991555344 is an abundant number, since it is smaller than the sum of its proper divisors (2124625416).

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

991555344 is a wasteful number, since it uses less digits than its factorization.

991555344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 519 (or 504 counting only the distinct ones).

The product of its digits is 486000, while the sum is 45.

The square root of 991555344 is about 31488.9717837849. The cubic root of 991555344 is about 997.1771537034.

The spelling of 991555344 in words is "nine hundred ninety-one million, five hundred fifty-five thousand, three hundred forty-four".