2161378757 has 2 divisors, whose sum is σ = 2161378758. Its totient is φ = 2161378756.

The previous prime is 2161378753. The next prime is 2161378783. The reversal of 2161378757 is 7578731612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1842899041 + 318479716 = 42929^2 + 17846^2 .

It is a cyclic number.

It is not a de Polignac number, because 2161378757 - 2² = 2161378753 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2161378753) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1080689378 + 1080689379.

It is an arithmetic number, because the mean of its divisors is an integer number (1080689379).

Almost surely, 2^2161378757 is an apocalyptic number.

It is an amenable number.

2161378757 is a deficient number, since it is larger than the sum of its proper divisors (1).

2161378757 is an equidigital number, since it uses as much as digits as its factorization.

2161378757 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 493920, while the sum is 47.

The square root of 2161378757 is about 46490.6308518179. The cubic root of 2161378757 is about 1292.9357964367.

The spelling of 2161378757 in words is "two billion, one hundred sixty-one million, three hundred seventy-eight thousand, seven hundred fifty-seven".