9999806400 has 840 divisors, whose sum is σ = 40244328960. Its totient is φ = 2426112000.

The previous prime is 9999806389. The next prime is 9999806407. The reversal of 9999806400 is 46089999.

It is a happy number.

It is a super-2 number, since 2×9999806400² (a number of 21 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 not an unprimeable number, because it can be changed into a prime (9999806407) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 76334335 + ... + 76334465.

Almost surely, 2^9999806400 is an apocalyptic number.

9999806400 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 9999806400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20122164480).

9999806400 is an abundant number, since it is smaller than the sum of its proper divisors (30244522560).

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

9999806400 is a wasteful number, since it uses less digits than its factorization.

9999806400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215 (or 191 counting only the distinct ones).

The product of its (nonzero) digits is 1259712, while the sum is 54.

The square root of 9999806400 is about 99999.0319953148. The cubic root of 9999806400 is about 2154.4207866570.

The spelling of 9999806400 in words is "nine billion, nine hundred ninety-nine million, eight hundred six thousand, four hundred".