645258739 has 2 divisors, whose sum is σ = 645258740. Its totient is φ = 645258738.

The previous prime is 645258737. The next prime is 645258763. The reversal of 645258739 is 937852546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645258739 - 2¹ = 645258737 is a prime.

Together with 645258737, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 645258692 and 645258701.

It is not a weakly prime, because it can be changed into another prime (645258737) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322629369 + 322629370.

It is an arithmetic number, because the mean of its divisors is an integer number (322629370).

Almost surely, 2^645258739 is an apocalyptic number.

645258739 is a deficient number, since it is larger than the sum of its proper divisors (1).

645258739 is an equidigital number, since it uses as much as digits as its factorization.

645258739 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1814400, while the sum is 49.

The square root of 645258739 is about 25401.9436067400. The cubic root of 645258739 is about 864.1277759377.

The spelling of 645258739 in words is "six hundred forty-five million, two hundred fifty-eight thousand, seven hundred thirty-nine".