991448757 has 54 divisors (see below), whose sum is σ = 1603365218. Its totient is φ = 586857600.

The previous prime is 991448743. The next prime is 991448767. The reversal of 991448757 is 757844199.

It can be written as a sum of positive squares in 3 ways, for example, as 127441521 + 864007236 = 11289^2 + 29394^2 .

It is not a de Polignac number, because 991448757 - 2⁶ = 991448693 is a prime.

Its product of digits (2540160) is a multiple of the sum of its prime divisors (128).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991448767) by changing a digit.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 13964032 + ... + 13964102.

Almost surely, 2^991448757 is an apocalyptic number.

It is an amenable number.

991448757 is a deficient number, since it is larger than the sum of its proper divisors (611916461).

991448757 is a wasteful number, since it uses less digits than its factorization.

991448757 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243 (or 128 counting only the distinct ones).

The product of its digits is 2540160, while the sum is 54.

The square root of 991448757 is about 31487.2792886270. The cubic root of 991448757 is about 997.1414219847.

The spelling of 991448757 in words is "nine hundred ninety-one million, four hundred forty-eight thousand, seven hundred fifty-seven".