1640403 has 24 divisors (see below), whose sum is σ = 2555280. Its totient is φ = 1010880.

The previous prime is 1640399. The next prime is 1640423. The reversal of 1640403 is 3040461.

It is not a de Polignac number, because 1640403 - 2² = 1640399 is a prime.

1640403 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1640423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8973 + ... + 9153.

It is an arithmetic number, because the mean of its divisors is an integer number (106470).

2^1640403 is an apocalyptic number.

1640403 is a deficient number, since it is larger than the sum of its proper divisors (914877).

1640403 is a wasteful number, since it uses less digits than its factorization.

1640403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259 (or 256 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 1640403 is about 1280.7821828867. The cubic root of 1640403 is about 117.9370295064.

Adding to 1640403 its reverse (3040461), we get a palindrome (4680864).

The spelling of 1640403 in words is "one million, six hundred forty thousand, four hundred three".