645171157 has 2 divisors, whose sum is σ = 645171158. Its totient is φ = 645171156.

The previous prime is 645171151. The next prime is 645171161. The reversal of 645171157 is 751171546.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 358004241 + 287166916 = 18921^2 + 16946^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645171157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645171151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322585578 + 322585579.

It is an arithmetic number, because the mean of its divisors is an integer number (322585579).

Almost surely, 2^645171157 is an apocalyptic number.

It is an amenable number.

645171157 is a deficient number, since it is larger than the sum of its proper divisors (1).

645171157 is an equidigital number, since it uses as much as digits as its factorization.

645171157 is an evil number, because the sum of its binary digits is even.

The product of its digits is 29400, while the sum is 37.

The square root of 645171157 is about 25400.2196250347. The cubic root of 645171157 is about 864.0886776873.

The spelling of 645171157 in words is "six hundred forty-five million, one hundred seventy-one thousand, one hundred fifty-seven".