1640305505 has 4 divisors (see below), whose sum is σ = 1968366612. Its totient is φ = 1312244400.

The previous prime is 1640305487. The next prime is 1640305523. The reversal of 1640305505 is 5055030461.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (1640305487) and next prime (1640305523).

It can be written as a sum of positive squares in 2 ways, for example, as 340919296 + 1299386209 = 18464^2 + 36047^2 .

It is not a de Polignac number, because 1640305505 - 2¹² = 1640301409 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 164030546 + ... + 164030555.

It is an arithmetic number, because the mean of its divisors is an integer number (492091653).

Almost surely, 2^1640305505 is an apocalyptic number.

It is an amenable number.

1640305505 is a deficient number, since it is larger than the sum of its proper divisors (328061107).

1640305505 is an equidigital number, since it uses as much as digits as its factorization.

1640305505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328061106.

The product of its (nonzero) digits is 9000, while the sum is 29.

The square root of 1640305505 is about 40500.6852411166. The cubic root of 1640305505 is about 1179.3469298732.

Adding to 1640305505 its reverse (5055030461), we get a palindrome (6695335966).

The spelling of 1640305505 in words is "one billion, six hundred forty million, three hundred five thousand, five hundred five".