78340636643 has 2 divisors, whose sum is σ = 78340636644. Its totient is φ = 78340636642.

The previous prime is 78340636601. The next prime is 78340636667. The reversal of 78340636643 is 34663604387.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78340636643 - 2¹⁸ = 78340374499 is a prime.

It is a super-2 number, since 2×78340636643² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 78340636591 and 78340636600.

It is not a weakly prime, because it can be changed into another prime (78340638643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39170318321 + 39170318322.

It is an arithmetic number, because the mean of its divisors is an integer number (39170318322).

Almost surely, 2^78340636643 is an apocalyptic number.

78340636643 is a deficient number, since it is larger than the sum of its proper divisors (1).

78340636643 is an equidigital number, since it uses as much as digits as its factorization.

78340636643 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5225472, while the sum is 50.

The spelling of 78340636643 in words is "seventy-eight billion, three hundred forty million, six hundred thirty-six thousand, six hundred forty-three".