991285197504 has 224 divisors, whose sum is σ = 3141982373376. Its totient is φ = 269889822720.

The previous prime is 991285197479. The next prime is 991285197559. The reversal of 991285197504 is 405791582199.

It is a tau number, because it is divible by the number of its divisors (224).

It is a super-4 number, since 4×991285197504⁴ (a number of 49 digits) contains 4444 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2160294 + ... + 2578650.

It is an arithmetic number, because the mean of its divisors is an integer number (14026707024).

Almost surely, 2^991285197504 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 991285197504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1570991186688).

991285197504 is an abundant number, since it is smaller than the sum of its proper divisors (2150697175872).

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

991285197504 is a wasteful number, since it uses less digits than its factorization.

991285197504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 418463 (or 418453 counting only the distinct ones).

The product of its (nonzero) digits is 8164800, while the sum is 60.

The spelling of 991285197504 in words is "nine hundred ninety-one billion, two hundred eighty-five million, one hundred ninety-seven thousand, five hundred four".