991164780144 has 2160 divisors, whose sum is σ = 4051364029440. Its totient is φ = 232794777600.

The previous prime is 991164780131. The next prime is 991164780157. The reversal of 991164780144 is 441087461199.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (991164780131) and next prime (991164780157).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 431 ways as a sum of consecutive naturals, for example, 13577599692 + ... + 13577599764.

Almost surely, 2^991164780144 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 991164780144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2025682014720).

991164780144 is an abundant number, since it is smaller than the sum of its proper divisors (3060199249296).

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

991164780144 is a wasteful number, since it uses less digits than its factorization.

991164780144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182 (or 146 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 54.

The spelling of 991164780144 in words is "nine hundred ninety-one billion, one hundred sixty-four million, seven hundred eighty thousand, one hundred forty-four".