64800781 has 2 divisors, whose sum is σ = 64800782. Its totient is φ = 64800780.

The previous prime is 64800779. The next prime is 64800829. The reversal of 64800781 is 18700846.

It is a happy number.

64800781 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., 63441225 + 1359556 = 7965^2 + 1166^2 .

It is a cyclic number.

It is not a de Polignac number, because 64800781 - 2¹ = 64800779 is a prime.

It is a super-2 number, since 2×64800781² = 8398282436419922, which contains 22 as substring.

Together with 64800779, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64804781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32400390 + 32400391.

It is an arithmetic number, because the mean of its divisors is an integer number (32400391).

Almost surely, 2^64800781 is an apocalyptic number.

It is an amenable number.

64800781 is a deficient number, since it is larger than the sum of its proper divisors (1).

64800781 is an equidigital number, since it uses as much as digits as its factorization.

64800781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 64800781 is about 8049.8932291056. The cubic root of 64800781 is about 401.6613837068.

The spelling of 64800781 in words is "sixty-four million, eight hundred thousand, seven hundred eighty-one".