646663769893 has 2 divisors, whose sum is σ = 646663769894. Its totient is φ = 646663769892.

The previous prime is 646663769867. The next prime is 646663770007. The reversal of 646663769893 is 398967366646.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 636354007524 + 10309762369 = 797718^2 + 101537^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646663769893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646663761893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323331884946 + 323331884947.

It is an arithmetic number, because the mean of its divisors is an integer number (323331884947).

Almost surely, 2^646663769893 is an apocalyptic number.

It is an amenable number.

646663769893 is a deficient number, since it is larger than the sum of its proper divisors (1).

646663769893 is an equidigital number, since it uses as much as digits as its factorization.

646663769893 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1269789696, while the sum is 73.

The spelling of 646663769893 in words is "six hundred forty-six billion, six hundred sixty-three million, seven hundred sixty-nine thousand, eight hundred ninety-three".