645203137 has 2 divisors, whose sum is σ = 645203138. Its totient is φ = 645203136.

The previous prime is 645203123. The next prime is 645203147. The reversal of 645203137 is 731302546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 635493681 + 9709456 = 25209^2 + 3116^2 .

It is a cyclic number.

It is not a de Polignac number, because 645203137 - 2¹⁹ = 644678849 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 645203099 and 645203108.

It is not a weakly prime, because it can be changed into another prime (645203147) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322601568 + 322601569.

It is an arithmetic number, because the mean of its divisors is an integer number (322601569).

Almost surely, 2^645203137 is an apocalyptic number.

It is an amenable number.

645203137 is a deficient number, since it is larger than the sum of its proper divisors (1).

645203137 is an equidigital number, since it uses as much as digits as its factorization.

645203137 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15120, while the sum is 31.

The square root of 645203137 is about 25400.8491393497. The cubic root of 645203137 is about 864.1029545703.

The spelling of 645203137 in words is "six hundred forty-five million, two hundred three thousand, one hundred thirty-seven".