19781983 has 12 divisors (see below), whose sum is σ = 22504440. Its totient is φ = 17238096.

The previous prime is 19781981. The next prime is 19781987. The reversal of 19781983 is 38918791.

It is not a de Polignac number, because 19781983 - 2¹ = 19781981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19781981) 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, 69760 + ... + 70042.

It is an arithmetic number, because the mean of its divisors is an integer number (1875370).

Almost surely, 2^19781983 is an apocalyptic number.

19781983 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

19781983 is a deficient number, since it is larger than the sum of its proper divisors (2722457).

19781983 is an equidigital number, since it uses as much as digits as its factorization.

19781983 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 598 (or 315 counting only the distinct ones).

The product of its digits is 108864, while the sum is 46.

The square root of 19781983 is about 4447.6941216770. The cubic root of 19781983 is about 270.4518405954.

The spelling of 19781983 in words is "nineteen million, seven hundred eighty-one thousand, nine hundred eighty-three".