991242256 has 45 divisors (see below), whose sum is σ = 2044565661. Its totient is φ = 465459456.

The previous prime is 991242251. The next prime is 991242257. The reversal of 991242256 is 652242199.

The square root of 991242256 is 31484.

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

It can be written as a sum of positive squares in only one way, i.e., 771728400 + 219513856 = 27780^2 + 14816^2 .

It is a super-2 number, since 2×991242256² = 1965122420159939072, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991242251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2140681 + ... + 2141143.

Almost surely, 2^991242256 is an apocalyptic number.

991242256 is the 31484-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991242256

991242256 is an abundant number, since it is smaller than the sum of its proper divisors (1053323405).

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

991242256 is an equidigital number, since it uses as much as digits as its factorization.

991242256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 968 (or 482 counting only the distinct ones).

The product of its digits is 77760, while the sum is 40.

The cubic root of 991242256 is about 997.0721882844.

The spelling of 991242256 in words is "nine hundred ninety-one million, two hundred forty-two thousand, two hundred fifty-six".