645606556079 has 2 divisors, whose sum is σ = 645606556080. Its totient is φ = 645606556078.

The previous prime is 645606555929. The next prime is 645606556093. The reversal of 645606556079 is 970655606546.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645606556079 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645606555079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322803278039 + 322803278040.

It is an arithmetic number, because the mean of its divisors is an integer number (322803278040).

Almost surely, 2^645606556079 is an apocalyptic number.

645606556079 is a deficient number, since it is larger than the sum of its proper divisors (1).

645606556079 is an equidigital number, since it uses as much as digits as its factorization.

645606556079 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40824000, while the sum is 59.

The spelling of 645606556079 in words is "six hundred forty-five billion, six hundred six million, five hundred fifty-six thousand, seventy-nine".