645695137 has 2 divisors, whose sum is σ = 645695138. Its totient is φ = 645695136.

The previous prime is 645695117. The next prime is 645695143. The reversal of 645695137 is 731596546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 327465216 + 318229921 = 18096^2 + 17839^2 .

It is a cyclic number.

It is not a de Polignac number, because 645695137 - 2¹⁹ = 645170849 is a prime.

It is not a weakly prime, because it can be changed into another prime (645695117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322847568 + 322847569.

It is an arithmetic number, because the mean of its divisors is an integer number (322847569).

Almost surely, 2^645695137 is an apocalyptic number.

It is an amenable number.

645695137 is a deficient number, since it is larger than the sum of its proper divisors (1).

645695137 is an equidigital number, since it uses as much as digits as its factorization.

645695137 is an evil number, because the sum of its binary digits is even.

The product of its digits is 680400, while the sum is 46.

The square root of 645695137 is about 25410.5320093854. The cubic root of 645695137 is about 864.3225394895.

The spelling of 645695137 in words is "six hundred forty-five million, six hundred ninety-five thousand, one hundred thirty-seven".