1981840320 has 84 divisors (see below), whose sum is σ = 6816714840. Its totient is φ = 528489984.

The previous prime is 1981840303. The next prime is 1981840321. The reversal of 1981840320 is 230481891.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981840321) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 341190 + ... + 346949.

Almost surely, 2^1981840320 is an apocalyptic number.

1981840320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1981840320 is an abundant number, since it is smaller than the sum of its proper divisors (4834874520).

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

1981840320 is a wasteful number, since it uses less digits than its factorization.

1981840320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 688162 (or 688149 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 1981840320 is about 44517.8651779260. The cubic root of 1981840320 is about 1256.0961561068.

The spelling of 1981840320 in words is "one billion, nine hundred eighty-one million, eight hundred forty thousand, three hundred twenty".