19821843799 has 4 divisors (see below), whose sum is σ = 20146792120. Its totient is φ = 19496895480.

The previous prime is 19821843791. The next prime is 19821843851. The reversal of 19821843799 is 99734812891.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19821843799 - 2³ = 19821843791 is a prime.

It is a super-3 number, since 3×19821843799³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (61), and also a Moran number because the ratio is a prime number: 324948259 = 19821843799 / (1 + 9 + 8 + 2 + 1 + 8 + 4 + 3 + 7 + 9 + 9).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19821843791) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 162474069 + ... + 162474190.

It is an arithmetic number, because the mean of its divisors is an integer number (5036698030).

Almost surely, 2^19821843799 is an apocalyptic number.

19821843799 is a deficient number, since it is larger than the sum of its proper divisors (324948321).

19821843799 is an equidigital number, since it uses as much as digits as its factorization.

19821843799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 324948320.

The product of its digits is 7838208, while the sum is 61.

The spelling of 19821843799 in words is "nineteen billion, eight hundred twenty-one million, eight hundred forty-three thousand, seven hundred ninety-nine".