991277705088 has 288 divisors, whose sum is σ = 3271730127120. Its totient is φ = 287325941760.

The previous prime is 991277705083. The next prime is 991277705107. The reversal of 991277705088 is 880507772199.

It is a tau number, because it is divible by the number of its divisors (288).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991277705083) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 3051420 + ... + 3360612.

Almost surely, 2^991277705088 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 991277705088, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1635865063560).

991277705088 is an abundant number, since it is smaller than the sum of its proper divisors (2280452422032).

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

991277705088 is a wasteful number, since it uses less digits than its factorization.

991277705088 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 309258 (or 309232 counting only the distinct ones).

The product of its (nonzero) digits is 17781120, while the sum is 63.

The spelling of 991277705088 in words is "nine hundred ninety-one billion, two hundred seventy-seven million, seven hundred five thousand, eighty-eight".