991280455545 has 64 divisors (see below), whose sum is σ = 1679625953280. Its totient is φ = 497832185088.

The previous prime is 991280455523. The next prime is 991280455553. The reversal of 991280455545 is 545554082199.

It is not a de Polignac number, because 991280455545 - 2²⁰ = 991279406969 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 61919932 + ... + 61935938.

It is an arithmetic number, because the mean of its divisors is an integer number (26244155520).

Almost surely, 2^991280455545 is an apocalyptic number.

991280455545 is a gapful number since it is divisible by the number (95) formed by its first and last digit.

It is an amenable number.

991280455545 is a deficient number, since it is larger than the sum of its proper divisors (688345497735).

991280455545 is a wasteful number, since it uses less digits than its factorization.

991280455545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17334.

The product of its (nonzero) digits is 12960000, while the sum is 57.

The spelling of 991280455545 in words is "nine hundred ninety-one billion, two hundred eighty million, four hundred fifty-five thousand, five hundred forty-five".