6445426681 has 2 divisors, whose sum is σ = 6445426682. Its totient is φ = 6445426680.

The previous prime is 6445426667. The next prime is 6445426727. The reversal of 6445426681 is 1866245446.

It is an a-pointer prime, because the next prime (6445426727) can be obtained adding 6445426681 to its sum of digits (46).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5270034025 + 1175392656 = 72595^2 + 34284^2 .

It is a cyclic number.

It is not a de Polignac number, because 6445426681 - 2¹¹ = 6445424633 is a prime.

It is a super-2 number, since 2×6445426681² = 83087050200293351522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (6445426081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3222713340 + 3222713341.

It is an arithmetic number, because the mean of its divisors is an integer number (3222713341).

Almost surely, 2^6445426681 is an apocalyptic number.

It is an amenable number.

6445426681 is a deficient number, since it is larger than the sum of its proper divisors (1).

6445426681 is an equidigital number, since it uses as much as digits as its factorization.

6445426681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1105920, while the sum is 46.

The square root of 6445426681 is about 80283.4147318112. The cubic root of 6445426681 is about 1861.0179305937.

The spelling of 6445426681 in words is "six billion, four hundred forty-five million, four hundred twenty-six thousand, six hundred eighty-one".