18202203821 has 4 divisors (see below), whose sum is σ = 18208349952. Its totient is φ = 18196057692.

The previous prime is 18202203791. The next prime is 18202203847. The reversal of 18202203821 is 12830220281.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12830220281 = 29 ⋅442421389.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18202203821 is a prime.

It is a super-3 number, since 3×18202203821³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18202203121) 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, 3068621 + ... + 3074546.

It is an arithmetic number, because the mean of its divisors is an integer number (4552087488).

Almost surely, 2^18202203821 is an apocalyptic number.

It is an amenable number.

18202203821 is a deficient number, since it is larger than the sum of its proper divisors (6146131).

18202203821 is an equidigital number, since it uses as much as digits as its factorization.

18202203821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6146130.

The product of its (nonzero) digits is 3072, while the sum is 29.

The spelling of 18202203821 in words is "eighteen billion, two hundred two million, two hundred three thousand, eight hundred twenty-one".