19981020 has 48 divisors (see below), whose sum is σ = 58383360. Its totient is φ = 5096256.

The previous prime is 19981007. The next prime is 19981021. The reversal of 19981020 is 2018991.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19981021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5860 + ... + 8619.

It is an arithmetic number, because the mean of its divisors is an integer number (1216320).

Almost surely, 2^19981020 is an apocalyptic number.

19981020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19981020 is an abundant number, since it is smaller than the sum of its proper divisors (38402340).

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

19981020 is a wasteful number, since it uses less digits than its factorization.

19981020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14514 (or 14512 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 30.

The square root of 19981020 is about 4470.0134227986. The cubic root of 19981020 is about 271.3558684056.

The spelling of 19981020 in words is "nineteen million, nine hundred eighty-one thousand, twenty".