64781 has 2 divisors, whose sum is σ = 64782. Its totient is φ = 64780.

The previous prime is 64763. The next prime is 64783. The reversal of 64781 is 18746.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52900 + 11881 = 230^2 + 109^2 .

It is a cyclic number.

It is not a de Polignac number, because 64781 - 2⁶ = 64717 is a prime.

It is a super-2 number, since 2×64781² = 8393155922, which contains 22 as substring.

Together with 64783, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 64781.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 64781.

It is not a weakly prime, because it can be changed into another prime (64783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32390 + 32391.

It is an arithmetic number, because the mean of its divisors is an integer number (32391).

2⁶⁴⁷⁸¹ is an apocalyptic number.

It is an amenable number.

64781 is a deficient number, since it is larger than the sum of its proper divisors (1).

64781 is an equidigital number, since it uses as much as digits as its factorization.

64781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1344, while the sum is 26.

The square root of 64781 is about 254.5211189666. The cubic root of 64781 is about 40.1620509341.

The spelling of 64781 in words is "sixty-four thousand, seven hundred eighty-one".