645256101401 has 2 divisors, whose sum is σ = 645256101402. Its totient is φ = 645256101400.

The previous prime is 645256101389. The next prime is 645256101443. The reversal of 645256101401 is 104101652546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 463353851401 + 181902250000 = 680701^2 + 426500^2 .

It is a cyclic number.

It is not a de Polignac number, because 645256101401 - 2²⁶ = 645188992537 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (645256107401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322628050700 + 322628050701.

It is an arithmetic number, because the mean of its divisors is an integer number (322628050701).

Almost surely, 2^645256101401 is an apocalyptic number.

It is an amenable number.

645256101401 is a deficient number, since it is larger than the sum of its proper divisors (1).

645256101401 is an equidigital number, since it uses as much as digits as its factorization.

645256101401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28800, while the sum is 35.

Adding to 645256101401 its reverse (104101652546), we get a palindrome (749357753947).

The spelling of 645256101401 in words is "six hundred forty-five billion, two hundred fifty-six million, one hundred one thousand, four hundred one".