991457280 has 416 divisors, whose sum is σ = 3868773120. Its totient is φ = 238878720.

The previous prime is 991457267. The next prime is 991457287. The reversal of 991457280 is 82754199.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991457287) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6082479 + ... + 6082641.

Almost surely, 2^991457280 is an apocalyptic number.

991457280 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991457280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1934386560).

991457280 is an abundant number, since it is smaller than the sum of its proper divisors (2877315840).

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

991457280 is a wasteful number, since it uses less digits than its factorization.

991457280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212 (or 184 counting only the distinct ones).

The product of its (nonzero) digits is 181440, while the sum is 45.

The square root of 991457280 is about 31487.4146287052. The cubic root of 991457280 is about 997.1442792888.

The spelling of 991457280 in words is "nine hundred ninety-one million, four hundred fifty-seven thousand, two hundred eighty".