1918645 has 4 divisors (see below), whose sum is σ = 2302380. Its totient is φ = 1534912.

The previous prime is 1918643. The next prime is 1918649. The reversal of 1918645 is 5468191.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5468191 = 181 ⋅30211.

It can be written as a sum of positive squares in 2 ways, for example, as 298116 + 1620529 = 546^2 + 1273^2 .

It is a cyclic number.

It is not a de Polignac number, because 1918645 - 2¹ = 1918643 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1918645.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1918643) 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, 191860 + ... + 191869.

It is an arithmetic number, because the mean of its divisors is an integer number (575595).

2^1918645 is an apocalyptic number.

It is an amenable number.

1918645 is a deficient number, since it is larger than the sum of its proper divisors (383735).

1918645 is an equidigital number, since it uses as much as digits as its factorization.

1918645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 383734.

The product of its digits is 8640, while the sum is 34.

The square root of 1918645 is about 1385.1516162500. The cubic root of 1918645 is about 124.2600551626.

It can be divided in two parts, 191 and 8645, that added together give a square (8836 = 94²).

The spelling of 1918645 in words is "one million, nine hundred eighteen thousand, six hundred forty-five".