18203821820 has 24 divisors (see below), whose sum is σ = 38272877664. Its totient is φ = 7272985536.

The previous prime is 18203821793. The next prime is 18203821841. The reversal of 18203821820 is 2812830281.

It is a super-2 number, since 2×18203821820² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

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, 516464 + ... + 550583.

It is an arithmetic number, because the mean of its divisors is an integer number (1594703236).

Almost surely, 2^18203821820 is an apocalyptic number.

18203821820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18203821820 is an abundant number, since it is smaller than the sum of its proper divisors (20069055844).

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

18203821820 is a wasteful number, since it uses less digits than its factorization.

18203821820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1067909 (or 1067907 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 35.

The spelling of 18203821820 in words is "eighteen billion, two hundred three million, eight hundred twenty-one thousand, eight hundred twenty".