1640523217 has 4 divisors (see below), whose sum is σ = 1640676276. Its totient is φ = 1640370160.

The previous prime is 1640523211. The next prime is 1640523221. The reversal of 1640523217 is 7123250461.

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

It can be written as a sum of positive squares in 2 ways, for example, as 626801296 + 1013721921 = 25036^2 + 31839^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1640523217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1640523211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59134 + ... + 82327.

It is an arithmetic number, because the mean of its divisors is an integer number (410169069).

Almost surely, 2^1640523217 is an apocalyptic number.

It is an amenable number.

1640523217 is a deficient number, since it is larger than the sum of its proper divisors (153059).

1640523217 is a wasteful number, since it uses less digits than its factorization.

1640523217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153058.

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 1640523217 is about 40503.3729089319. The cubic root of 1640523217 is about 1179.3991044263.

Adding to 1640523217 its reverse (7123250461), we get a palindrome (8763773678).

The spelling of 1640523217 in words is "one billion, six hundred forty million, five hundred twenty-three thousand, two hundred seventeen".