1991539200 has 480 divisors, whose sum is σ = 7793786880. Its totient is φ = 438681600.

The previous prime is 1991539181. The next prime is 1991539241. The reversal of 1991539200 is 29351991.

It is a tau number, because it is divible by the number of its divisors (480).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 8332681 + ... + 8332919.

It is an arithmetic number, because the mean of its divisors is an integer number (16237056).

Almost surely, 2^1991539200 is an apocalyptic number.

1991539200 is a gapful number since it is divisible by the number (10) 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 1991539200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3896893440).

1991539200 is an abundant number, since it is smaller than the sum of its proper divisors (5802247680).

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

1991539200 is a wasteful number, since it uses less digits than its factorization.

1991539200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308 (or 287 counting only the distinct ones).

The product of its (nonzero) digits is 21870, while the sum is 39.

The square root of 1991539200 is about 44626.6646748331. The cubic root of 1991539200 is about 1258.1418819975.

The spelling of 1991539200 in words is "one billion, nine hundred ninety-one million, five hundred thirty-nine thousand, two hundred".