78638047 has 2 divisors, whose sum is σ = 78638048. Its totient is φ = 78638046.

The previous prime is 78638033. The next prime is 78638057. The reversal of 78638047 is 74083687.

It is a strong prime.

It is an emirp because it is prime and its reverse (74083687) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78638047 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 78637994 and 78638012.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78638057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39319023 + 39319024.

It is an arithmetic number, because the mean of its divisors is an integer number (39319024).

Almost surely, 2^78638047 is an apocalyptic number.

78638047 is a deficient number, since it is larger than the sum of its proper divisors (1).

78638047 is an equidigital number, since it uses as much as digits as its factorization.

78638047 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 225792, while the sum is 43.

The square root of 78638047 is about 8867.8095942572. The cubic root of 78638047 is about 428.4277302419.

The spelling of 78638047 in words is "seventy-eight million, six hundred thirty-eight thousand, forty-seven".