78278647 has 2 divisors, whose sum is σ = 78278648. Its totient is φ = 78278646.

The previous prime is 78278639. The next prime is 78278701. The reversal of 78278647 is 74687287.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78278647 - 2³ = 78278639 is a prime.

It is a super-2 number, since 2×78278647² = 12255093152301218, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78278647.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78278747) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39139323 + 39139324.

It is an arithmetic number, because the mean of its divisors is an integer number (39139324).

Almost surely, 2^78278647 is an apocalyptic number.

78278647 is a deficient number, since it is larger than the sum of its proper divisors (1).

78278647 is an equidigital number, since it uses as much as digits as its factorization.

78278647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1053696, while the sum is 49.

The square root of 78278647 is about 8847.5220824816. The cubic root of 78278647 is about 427.7740513359.

The spelling of 78278647 in words is "seventy-eight million, two hundred seventy-eight thousand, six hundred forty-seven".