1816666801506 has 24 divisors (see below), whose sum is σ = 3936243203100. Its totient is φ = 605535323616.

The previous prime is 1816666801501. The next prime is 1816666801513. The reversal of 1816666801506 is 6051086666181.

It can be written as a sum of positive squares in 2 ways, for example, as 1784107847025 + 32558954481 = 1335705^2 + 180441^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1816666801501) 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, 1132281 + ... + 2217068.

Almost surely, 2^{1816666801506} is an apocalyptic number.

1816666801506 is an abundant number, since it is smaller than the sum of its proper divisors (2119576401594).

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

1816666801506 is a wasteful number, since it uses less digits than its factorization.

1816666801506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3379490 (or 3379487 counting only the distinct ones).

The product of its (nonzero) digits is 2488320, while the sum is 54.

The spelling of 1816666801506 in words is "one trillion, eight hundred sixteen billion, six hundred sixty-six million, eight hundred one thousand, five hundred six".