1964594942581 has 4 divisors (see below), whose sum is σ = 1964600585100. Its totient is φ = 1964589300064.

The previous prime is 1964594942521. The next prime is 1964594942623. The reversal of 1964594942581 is 1852494954691.

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 405195902500 + 1559399040081 = 636550^2 + 1248759^2 .

It is a cyclic number.

It is not a de Polignac number, because 1964594942581 - 2²³ = 1964586553973 is a prime.

It is a super-2 number, since 2×1964594942581² (a number of 25 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (67) 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 (1964594942521) 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, 2262046 + ... + 3007663.

It is an arithmetic number, because the mean of its divisors is an integer number (491150146275).

Almost surely, 2^{1964594942581} is an apocalyptic number.

It is an amenable number.

1964594942581 is a deficient number, since it is larger than the sum of its proper divisors (5642519).

1964594942581 is an equidigital number, since it uses as much as digits as its factorization.

1964594942581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5642518.

The product of its digits is 111974400, while the sum is 67.

The spelling of 1964594942581 in words is "one trillion, nine hundred sixty-four billion, five hundred ninety-four million, nine hundred forty-two thousand, five hundred eighty-one".