18720033821 has 4 divisors (see below), whose sum is σ = 18720789600. Its totient is φ = 18719278044.

The previous prime is 18720033817. The next prime is 18720033833. The reversal of 18720033821 is 12833002781.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18720033821 - 2² = 18720033817 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 (18720033881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 339431 + ... + 390708.

It is an arithmetic number, because the mean of its divisors is an integer number (4680197400).

Almost surely, 2^18720033821 is an apocalyptic number.

It is an amenable number.

18720033821 is a deficient number, since it is larger than the sum of its proper divisors (755779).

18720033821 is an equidigital number, since it uses as much as digits as its factorization.

18720033821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 755778.

The product of its (nonzero) digits is 16128, while the sum is 35.

The spelling of 18720033821 in words is "eighteen billion, seven hundred twenty million, thirty-three thousand, eight hundred twenty-one".