18218781578331 has 12 divisors (see below), whose sum is σ = 26316056290680. Its totient is φ = 12145836636960.

The previous prime is 18218781578321. The next prime is 18218781578359. The reversal of 18218781578331 is 13387518781281.

18218781578331 is a `hidden beast` number, since 1 + 8 + 21 + 8 + 7 + 8 + 1 + 578 + 3 + 31 = 666.

It is not a de Polignac number, because 18218781578331 - 2¹⁴ = 18218781561947 is a prime.

It is a super-2 number, since 2×18218781578331² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18218781578321) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8733175 + ... + 10616303.

It is an arithmetic number, because the mean of its divisors is an integer number (2193004690890).

Almost surely, 2^{18218781578331} is an apocalyptic number.

18218781578331 is a deficient number, since it is larger than the sum of its proper divisors (8097274712349).

18218781578331 is a wasteful number, since it uses less digits than its factorization.

18218781578331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2958106 (or 2958103 counting only the distinct ones).

The product of its digits is 18063360, while the sum is 63.

The spelling of 18218781578331 in words is "eighteen trillion, two hundred eighteen billion, seven hundred eighty-one million, five hundred seventy-eight thousand, three hundred thirty-one".