78216647 has 2 divisors, whose sum is σ = 78216648. Its totient is φ = 78216646.

The previous prime is 78216637. The next prime is 78216667. The reversal of 78216647 is 74661287.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78216647 - 2¹² = 78212551 is a prime.

It is a super-2 number, since 2×78216647² = 12235687735845218, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78216637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39108323 + 39108324.

It is an arithmetic number, because the mean of its divisors is an integer number (39108324).

Almost surely, 2^78216647 is an apocalyptic number.

78216647 is a deficient number, since it is larger than the sum of its proper divisors (1).

78216647 is an equidigital number, since it uses as much as digits as its factorization.

78216647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 112896, while the sum is 41.

The square root of 78216647 is about 8844.0175825244. The cubic root of 78216647 is about 427.6610831236.

The spelling of 78216647 in words is "seventy-eight million, two hundred sixteen thousand, six hundred forty-seven".