981121680 has 640 divisors, whose sum is σ = 4473999360. Its totient is φ = 191324160.

The previous prime is 981121667. The next prime is 981121681. The reversal of 981121680 is 86121189.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (981121681) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 2827267 + ... + 2827613.

It is an arithmetic number, because the mean of its divisors is an integer number (6990624).

Almost surely, 2^981121680 is an apocalyptic number.

981121680 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 981121680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2236999680).

981121680 is an abundant number, since it is smaller than the sum of its proper divisors (3492877680).

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

981121680 is a wasteful number, since it uses less digits than its factorization.

981121680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404 (or 392 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 36.

The square root of 981121680 is about 31322.8619382074. The cubic root of 981121680 is about 993.6672070576.

The spelling of 981121680 in words is "nine hundred eighty-one million, one hundred twenty-one thousand, six hundred eighty".