1818539997321 has 16 divisors (see below), whose sum is σ = 2525958832320. Its totient is φ = 1162742945280.

The previous prime is 1818539997277. The next prime is 1818539997331. The reversal of 1818539997321 is 1237999358181.

It is not a de Polignac number, because 1818539997321 - 2⁷ = 1818539997193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1818539997331) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 125288320 + ... + 125302833.

It is an arithmetic number, because the mean of its divisors is an integer number (157872427020).

Almost surely, 2^{1818539997321} is an apocalyptic number.

It is an amenable number.

1818539997321 is a deficient number, since it is larger than the sum of its proper divisors (707418834999).

1818539997321 is a wasteful number, since it uses less digits than its factorization.

1818539997321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 250591256.

The product of its digits is 29393280, while the sum is 66.

The spelling of 1818539997321 in words is "one trillion, eight hundred eighteen billion, five hundred thirty-nine million, nine hundred ninety-seven thousand, three hundred twenty-one".