645606556093 has 2 divisors, whose sum is σ = 645606556094. Its totient is φ = 645606556092.

The previous prime is 645606556079. The next prime is 645606556139. The reversal of 645606556093 is 390655606546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 377337461284 + 268269094809 = 614278^2 + 517947^2 .

It is a cyclic number.

It is not a de Polignac number, because 645606556093 - 2¹⁷ = 645606425021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645606556193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322803278046 + 322803278047.

It is an arithmetic number, because the mean of its divisors is an integer number (322803278047).

Almost surely, 2^645606556093 is an apocalyptic number.

It is an amenable number.

645606556093 is a deficient number, since it is larger than the sum of its proper divisors (1).

645606556093 is an equidigital number, since it uses as much as digits as its factorization.

645606556093 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17496000, while the sum is 55.

The spelling of 645606556093 in words is "six hundred forty-five billion, six hundred six million, five hundred fifty-six thousand, ninety-three".