1981658880 has 324 divisors, whose sum is σ = 7124218920. Its totient is φ = 508538880.

The previous prime is 1981658879. The next prime is 1981658897. The reversal of 1981658880 is 888561891.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 11070631 + ... + 11070809.

It is an arithmetic number, because the mean of its divisors is an integer number (21988330).

Almost surely, 2^1981658880 is an apocalyptic number.

1981658880 is a gapful number since it is divisible by the number (10) 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 1981658880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3562109460).

1981658880 is an abundant number, since it is smaller than the sum of its proper divisors (5142560040).

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

1981658880 is a wasteful number, since it uses less digits than its factorization.

1981658880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268 (or 220 counting only the distinct ones).

The product of its (nonzero) digits is 1105920, while the sum is 54.

The square root of 1981658880 is about 44515.8272977151. The cubic root of 1981658880 is about 1256.0578225371.

The spelling of 1981658880 in words is "one billion, nine hundred eighty-one million, six hundred fifty-eight thousand, eight hundred eighty".