613812906821 has 2 divisors, whose sum is σ = 613812906822. Its totient is φ = 613812906820.

The previous prime is 613812906779. The next prime is 613812906907. The reversal of 613812906821 is 128609218316.

It is a happy number.

613812906821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 598009902721 + 15803004100 = 773311^2 + 125710^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-613812906821 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (613812906221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 306906453410 + 306906453411.

It is an arithmetic number, because the mean of its divisors is an integer number (306906453411).

Almost surely, 2^613812906821 is an apocalyptic number.

It is an amenable number.

613812906821 is a deficient number, since it is larger than the sum of its proper divisors (1).

613812906821 is an equidigital number, since it uses as much as digits as its factorization.

613812906821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 248832, while the sum is 47.

The spelling of 613812906821 in words is "six hundred thirteen billion, eight hundred twelve million, nine hundred six thousand, eight hundred twenty-one".