646064052581 has 2 divisors, whose sum is σ = 646064052582. Its totient is φ = 646064052580.

The previous prime is 646064052547. The next prime is 646064052703. The reversal of 646064052581 is 185250460646.

646064052581 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., 388959279556 + 257104773025 = 623666^2 + 507055^2 .

It is a cyclic number.

It is not a de Polignac number, because 646064052581 - 2¹⁴ = 646064036197 is a prime.

It is a super-2 number, since 2×646064052581² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646064052511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323032026290 + 323032026291.

It is an arithmetic number, because the mean of its divisors is an integer number (323032026291).

Almost surely, 2^646064052581 is an apocalyptic number.

It is an amenable number.

646064052581 is a deficient number, since it is larger than the sum of its proper divisors (1).

646064052581 is an equidigital number, since it uses as much as digits as its factorization.

646064052581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1382400, while the sum is 47.

The spelling of 646064052581 in words is "six hundred forty-six billion, sixty-four million, fifty-two thousand, five hundred eighty-one".