65778613 has 2 divisors, whose sum is σ = 65778614. Its totient is φ = 65778612.

The previous prime is 65778611. The next prime is 65778619. The reversal of 65778613 is 31687756.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65173329 + 605284 = 8073^2 + 778^2 .

It is a cyclic number.

It is not a de Polignac number, because 65778613 - 2¹ = 65778611 is a prime.

Together with 65778611, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 65778613.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65778611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32889306 + 32889307.

It is an arithmetic number, because the mean of its divisors is an integer number (32889307).

Almost surely, 2^65778613 is an apocalyptic number.

It is an amenable number.

65778613 is a deficient number, since it is larger than the sum of its proper divisors (1).

65778613 is an equidigital number, since it uses as much as digits as its factorization.

65778613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 211680, while the sum is 43.

The square root of 65778613 is about 8110.4015313670. The cubic root of 65778613 is about 403.6716383113.

The spelling of 65778613 in words is "sixty-five million, seven hundred seventy-eight thousand, six hundred thirteen".