1640136645265 has 4 divisors (see below), whose sum is σ = 1968163974324. Its totient is φ = 1312109316208.

The previous prime is 1640136645263. The next prime is 1640136645293. The reversal of 1640136645265 is 5625466310461.

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 299858093649 + 1340278551616 = 547593^2 + 1157704^2 .

It is a cyclic number.

It is not a de Polignac number, because 1640136645265 - 2¹ = 1640136645263 is a prime.

It is a super-2 number, since 2×1640136645265² (a number of 25 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (49) 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 not an unprimeable number, because it can be changed into a prime (1640136645263) 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, 164013664522 + ... + 164013664531.

It is an arithmetic number, because the mean of its divisors is an integer number (492040993581).

Almost surely, 2^{1640136645265} is an apocalyptic number.

It is an amenable number.

1640136645265 is a deficient number, since it is larger than the sum of its proper divisors (328027329059).

1640136645265 is an equidigital number, since it uses as much as digits as its factorization.

1640136645265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 328027329058.

The product of its (nonzero) digits is 3110400, while the sum is 49.

The spelling of 1640136645265 in words is "one trillion, six hundred forty billion, one hundred thirty-six million, six hundred forty-five thousand, two hundred sixty-five".