2139568645 has 4 divisors (see below), whose sum is σ = 2567482380. Its totient is φ = 1711654912.

The previous prime is 2139568631. The next prime is 2139568649. The reversal of 2139568645 is 5468659312.

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 414163201 + 1725405444 = 20351^2 + 41538^2 .

It is a cyclic number.

It is not a de Polignac number, because 2139568645 - 2⁷ = 2139568517 is a prime.

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 congruent number.

It is not an unprimeable number, because it can be changed into a prime (2139568649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 213956860 + ... + 213956869.

It is an arithmetic number, because the mean of its divisors is an integer number (641870595).

Almost surely, 2^2139568645 is an apocalyptic number.

It is an amenable number.

2139568645 is a deficient number, since it is larger than the sum of its proper divisors (427913735).

2139568645 is an equidigital number, since it uses as much as digits as its factorization.

2139568645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 427913734.

The product of its digits is 1555200, while the sum is 49.

The square root of 2139568645 is about 46255.4715141895. The cubic root of 2139568645 is about 1288.5721527065.

The spelling of 2139568645 in words is "two billion, one hundred thirty-nine million, five hundred sixty-eight thousand, six hundred forty-five".