1866217813 has 4 divisors (see below), whose sum is σ = 1869262828. Its totient is φ = 1863172800.

The previous prime is 1866217783. The next prime is 1866217817. The reversal of 1866217813 is 3187126681.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 56821444 + 1809396369 = 7538^2 + 42537^2 .

It is a cyclic number.

It is not a de Polignac number, because 1866217813 - 2⁵ = 1866217781 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1866217813.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1866217817) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1521588 + ... + 1522813.

It is an arithmetic number, because the mean of its divisors is an integer number (467315707).

Almost surely, 2^1866217813 is an apocalyptic number.

It is an amenable number.

1866217813 is a deficient number, since it is larger than the sum of its proper divisors (3045015).

1866217813 is an equidigital number, since it uses as much as digits as its factorization.

1866217813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3045014.

The product of its digits is 96768, while the sum is 43.

The square root of 1866217813 is about 43199.7432052553. The cubic root of 1866217813 is about 1231.1778025709.

The spelling of 1866217813 in words is "one billion, eight hundred sixty-six million, two hundred seventeen thousand, eight hundred thirteen".