1640818 has 4 divisors (see below), whose sum is σ = 2461230. Its totient is φ = 820408.

The previous prime is 1640809. The next prime is 1640819. The reversal of 1640818 is 8180461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8180461 = 541 ⋅15121.

It can be written as a sum of positive squares in only one way, i.e., 1247689 + 393129 = 1117^2 + 627^2 .

It is not an unprimeable number, because it can be changed into a prime (1640819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410203 + ... + 410206.

2^1640818 is an apocalyptic number.

1640818 is a deficient number, since it is larger than the sum of its proper divisors (820412).

1640818 is an equidigital number, since it uses as much as digits as its factorization.

1640818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 820411.

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 1640818 is about 1280.9441830150. The cubic root of 1640818 is about 117.9469741644.

The spelling of 1640818 in words is "one million, six hundred forty thousand, eight hundred eighteen".