991577084400 has 600 divisors, whose sum is σ = 4281150135680. Its totient is φ = 214716510720.

The previous prime is 991577084341. The next prime is 991577084431. The reversal of 991577084400 is 4480775199.

991577084400 is a `hidden beast` number, since 9 + 9 + 157 + 7 + 0 + 84 + 400 = 666.

It is a tau number, because it is divible by the number of its divisors (600).

It is a super-2 number, since 2×991577084400² (a number of 25 digits) contains 22 as substring.

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 119 ways as a sum of consecutive naturals, for example, 4194147 + ... + 4424253.

Almost surely, 2^991577084400 is an apocalyptic number.

991577084400 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 991577084400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2140575067840).

991577084400 is an abundant number, since it is smaller than the sum of its proper divisors (3289573051280).

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

991577084400 is a wasteful number, since it uses less digits than its factorization.

991577084400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230163 (or 230143 counting only the distinct ones).

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

The spelling of 991577084400 in words is "nine hundred ninety-one billion, five hundred seventy-seven million, eighty-four thousand, four hundred".