999981684450 has 288 divisors, whose sum is σ = 3178377820800. Its totient is φ = 220541045760.

The previous prime is 999981684409. The next prime is 999981684451. The reversal of 999981684450 is 54486189999.

999981684450 is a `hidden beast` number, since 9 + 9 + 9 + 9 + 8 + 168 + 4 + 450 = 666.

It is not an unprimeable number, because it can be changed into a prime (999981684451) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 201241566 + ... + 201246534.

It is an arithmetic number, because the mean of its divisors is an integer number (11036034100).

Almost surely, 2^999981684450 is an apocalyptic number.

999981684450 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 999981684450, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1589188910400).

999981684450 is an abundant number, since it is smaller than the sum of its proper divisors (2178396136350).

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

999981684450 is a wasteful number, since it uses less digits than its factorization.

999981684450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7226 (or 7218 counting only the distinct ones).

The product of its (nonzero) digits is 201553920, while the sum is 72.

The spelling of 999981684450 in words is "nine hundred ninety-nine billion, nine hundred eighty-one million, six hundred eighty-four thousand, four hundred fifty".