2171157217 has 2 divisors, whose sum is σ = 2171157218. Its totient is φ = 2171157216.

The previous prime is 2171157127. The next prime is 2171157221. The reversal of 2171157217 is 7127511712.

Together with previous prime (2171157127) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2025810081 + 145347136 = 45009^2 + 12056^2 .

It is a cyclic number.

It is not a de Polignac number, because 2171157217 - 2¹¹ = 2171155169 is a prime.

It is not a weakly prime, because it can be changed into another prime (2171157517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1085578608 + 1085578609.

It is an arithmetic number, because the mean of its divisors is an integer number (1085578609).

Almost surely, 2^2171157217 is an apocalyptic number.

It is an amenable number.

2171157217 is a deficient number, since it is larger than the sum of its proper divisors (1).

2171157217 is an equidigital number, since it uses as much as digits as its factorization.

2171157217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6860, while the sum is 34.

The square root of 2171157217 is about 46595.6780935743. The cubic root of 2171157217 is about 1294.8826868084.

Adding to 2171157217 its reverse (7127511712), we get a palindrome (9298668929).

The spelling of 2171157217 in words is "two billion, one hundred seventy-one million, one hundred fifty-seven thousand, two hundred seventeen".