78139147 has 2 divisors, whose sum is σ = 78139148. Its totient is φ = 78139146.

The previous prime is 78139099. The next prime is 78139181. The reversal of 78139147 is 74193187.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78139147 is a prime.

It is a super-2 number, since 2×78139147² = 12211452587775218, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78139847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39069573 + 39069574.

It is an arithmetic number, because the mean of its divisors is an integer number (39069574).

Almost surely, 2^78139147 is an apocalyptic number.

78139147 is a deficient number, since it is larger than the sum of its proper divisors (1).

78139147 is an equidigital number, since it uses as much as digits as its factorization.

78139147 is an evil number, because the sum of its binary digits is even.

The product of its digits is 42336, while the sum is 40.

The square root of 78139147 is about 8839.6350037770. The cubic root of 78139147 is about 427.5197888768.

The spelling of 78139147 in words is "seventy-eight million, one hundred thirty-nine thousand, one hundred forty-seven".