2156311897 has 2 divisors, whose sum is σ = 2156311898. Its totient is φ = 2156311896.

The previous prime is 2156311877. The next prime is 2156311967. The reversal of 2156311897 is 7981136512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2156302096 + 9801 = 46436^2 + 99^2 .

It is a cyclic number.

It is not a de Polignac number, because 2156311897 - 2¹¹ = 2156309849 is a prime.

It is not a weakly prime, because it can be changed into another prime (2156311867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1078155948 + 1078155949.

It is an arithmetic number, because the mean of its divisors is an integer number (1078155949).

Almost surely, 2^2156311897 is an apocalyptic number.

It is an amenable number.

2156311897 is a deficient number, since it is larger than the sum of its proper divisors (1).

2156311897 is an equidigital number, since it uses as much as digits as its factorization.

2156311897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90720, while the sum is 43.

The square root of 2156311897 is about 46436.1055322257. The cubic root of 2156311897 is about 1291.9246747885.

The spelling of 2156311897 in words is "two billion, one hundred fifty-six million, three hundred eleven thousand, eight hundred ninety-seven".