1918564685 has 4 divisors (see below), whose sum is σ = 2302277628. Its totient is φ = 1534851744.

The previous prime is 1918564651. The next prime is 1918564693. The reversal of 1918564685 is 5864658191.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5864658191 = 7 ⋅837808313.

It can be written as a sum of positive squares in 2 ways, for example, as 1225980196 + 692584489 = 35014^2 + 26317^2 .

It is a cyclic number.

It is not a de Polignac number, because 1918564685 - 2⁶ = 1918564621 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 191856464 + ... + 191856473.

It is an arithmetic number, because the mean of its divisors is an integer number (575569407).

Almost surely, 2^1918564685 is an apocalyptic number.

It is an amenable number.

1918564685 is a deficient number, since it is larger than the sum of its proper divisors (383712943).

1918564685 is an equidigital number, since it uses as much as digits as its factorization.

1918564685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 383712942.

The product of its digits is 2073600, while the sum is 53.

The square root of 1918564685 is about 43801.4233216228. The cubic root of 1918564685 is about 1242.5832128522.

The spelling of 1918564685 in words is "one billion, nine hundred eighteen million, five hundred sixty-four thousand, six hundred eighty-five".