9978211800 has 576 divisors, whose sum is σ = 37047628800. Its totient is φ = 2491430400.

The previous prime is 9978211787. The next prime is 9978211807. The reversal of 9978211800 is 81128799.

It is a super-3 number, since 3×9978211800³ (a number of 31 digits) contains 333 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9978211807) 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, 55744111 + ... + 55744289.

It is an arithmetic number, because the mean of its divisors is an integer number (64318800).

Almost surely, 2^9978211800 is an apocalyptic number.

9978211800 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 9978211800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18523814400).

9978211800 is an abundant number, since it is smaller than the sum of its proper divisors (27069417000).

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

9978211800 is a wasteful number, since it uses less digits than its factorization.

9978211800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278 (or 257 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 45.

The square root of 9978211800 is about 99890.9995945581. Note that the first 3 decimals coincide. The cubic root of 9978211800 is about 2152.8688437845.

The spelling of 9978211800 in words is "nine billion, nine hundred seventy-eight million, two hundred eleven thousand, eight hundred".