1640706317 has 16 divisors (see below), whose sum is σ = 1689816048. Its totient is φ = 1592524800.

The previous prime is 1640706299. The next prime is 1640706343. The reversal of 1640706317 is 7136070461.

It can be written as a sum of positive squares in 8 ways, for example, as 189172516 + 1451533801 = 13754^2 + 38099^2 .

It is a cyclic number.

It is not a de Polignac number, because 1640706317 - 2¹⁰ = 1640705293 is a prime.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640705317) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1422413 + ... + 1423565.

It is an arithmetic number, because the mean of its divisors is an integer number (105613503).

Almost surely, 2^1640706317 is an apocalyptic number.

It is an amenable number.

1640706317 is a deficient number, since it is larger than the sum of its proper divisors (49109731).

1640706317 is a wasteful number, since it uses less digits than its factorization.

1640706317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1520.

The product of its (nonzero) digits is 21168, while the sum is 35.

The square root of 1640706317 is about 40505.6331514519. The cubic root of 1640706317 is about 1179.4429806605.

Adding to 1640706317 its reverse (7136070461), we get a palindrome (8776776778).

The spelling of 1640706317 in words is "one billion, six hundred forty million, seven hundred six thousand, three hundred seventeen".