1806206561781 has 16 divisors (see below), whose sum is σ = 2497723862400. Its totient is φ = 1159626966848.

The previous prime is 1806206561767. The next prime is 1806206561813. The reversal of 1806206561781 is 1871656026081.

It is a cyclic number.

It is not a de Polignac number, because 1806206561781 - 2¹⁰ = 1806206560757 is a prime.

It is a super-2 number, since 2×1806206561781² (a number of 25 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1806206561741) 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, 26651241 + ... + 26718926.

It is an arithmetic number, because the mean of its divisors is an integer number (156107741400).

Almost surely, 2^{1806206561781} is an apocalyptic number.

It is an amenable number.

1806206561781 is a deficient number, since it is larger than the sum of its proper divisors (691517300619).

1806206561781 is a wasteful number, since it uses less digits than its factorization.

1806206561781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53370588.

The product of its (nonzero) digits is 967680, while the sum is 51.

The spelling of 1806206561781 in words is "one trillion, eight hundred six billion, two hundred six million, five hundred sixty-one thousand, seven hundred eighty-one".