1999819820 has 24 divisors (see below), whose sum is σ = 4446658944. Its totient is φ = 752873216.

The previous prime is 1999819817. The next prime is 1999819831. The reversal of 1999819820 is 289189991.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2940572 + ... + 2941251.

It is an arithmetic number, because the mean of its divisors is an integer number (185277456).

Almost surely, 2^1999819820 is an apocalyptic number.

1999819820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1999819820 is an abundant number, since it is smaller than the sum of its proper divisors (2446839124).

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

1999819820 is a wasteful number, since it uses less digits than its factorization.

1999819820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5881849 (or 5881847 counting only the distinct ones).

The product of its (nonzero) digits is 839808, while the sum is 56.

The square root of 1999819820 is about 44719.3450309818. The cubic root of 1999819820 is about 1259.8832133295.

The spelling of 1999819820 in words is "one billion, nine hundred ninety-nine million, eight hundred nineteen thousand, eight hundred twenty".