99721036800 has 1782 divisors, whose sum is σ = 462786951354. Its totient is φ = 20437401600.

The previous prime is 99721036787. The next prime is 99721036813. The reversal of 99721036800 is 863012799.

It is an interprime number because it is at equal distance from previous prime (99721036787) and next prime (99721036813).

It can be written as a sum of positive squares in 3 ways, for example, as 7868399616 + 91852637184 = 88704^2 + 303072^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 161 ways as a sum of consecutive naturals, for example, 1366041564 + ... + 1366041636.

Almost surely, 2^99721036800 is an apocalyptic number.

99721036800 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 99721036800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (231393475677).

99721036800 is an abundant number, since it is smaller than the sum of its proper divisors (363065914554).

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

99721036800 is a wasteful number, since it uses less digits than its factorization.

99721036800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145 (or 101 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 45.

The spelling of 99721036800 in words is "ninety-nine billion, seven hundred twenty-one million, thirty-six thousand, eight hundred".