1640505 has 8 divisors (see below), whose sum is σ = 2624832. Its totient is φ = 874928.

The previous prime is 1640503. The next prime is 1640519. The reversal of 1640505 is 5050461.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1640505 - 2¹ = 1640503 is a prime.

It is a Curzon number.

1640505 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1640503) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54669 + ... + 54698.

It is an arithmetic number, because the mean of its divisors is an integer number (328104).

2^1640505 is an apocalyptic number.

1640505 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1640505 is a deficient number, since it is larger than the sum of its proper divisors (984327).

1640505 is a wasteful number, since it uses less digits than its factorization.

1640505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109375.

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 1640505 is about 1280.8220016849. The cubic root of 1640505 is about 117.9394738910.

Adding to 1640505 its reverse (5050461), we get a palindrome (6690966).

It can be divided in two parts, 1640 and 505, that added together give a triangular number (2145 = T₆₅).

The spelling of 1640505 in words is "one million, six hundred forty thousand, five hundred five".