1821237638418 has 48 divisors (see below), whose sum is σ = 4304835115776. Its totient is φ = 551878449120.

The previous prime is 1821237638417. The next prime is 1821237638443. The reversal of 1821237638418 is 8148367321281.

1821237638418 is a `hidden beast` number, since 1 + 8 + 2 + 123 + 76 + 38 + 418 = 666.

It is not an unprimeable number, because it can be changed into a prime (1821237638417) 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 23 ways as a sum of consecutive naturals, for example, 15457980 + ... + 15575352.

It is an arithmetic number, because the mean of its divisors is an integer number (89684064912).

Almost surely, 2^{1821237638418} is an apocalyptic number.

1821237638418 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1821237638418 is an abundant number, since it is smaller than the sum of its proper divisors (2483597477358).

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

1821237638418 is a wasteful number, since it uses less digits than its factorization.

1821237638418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195759 (or 195756 counting only the distinct ones).

The product of its digits is 3096576, while the sum is 54.

The spelling of 1821237638418 in words is "one trillion, eight hundred twenty-one billion, two hundred thirty-seven million, six hundred thirty-eight thousand, four hundred eighteen".