78278477 has 2 divisors, whose sum is σ = 78278478. Its totient is φ = 78278476.

The previous prime is 78278443. The next prime is 78278479. The reversal of 78278477 is 77487287.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 53963716 + 24314761 = 7346^2 + 4931^2 .

It is a cyclic number.

It is not a de Polignac number, because 78278477 - 2⁶ = 78278413 is a prime.

It is a super-2 number, since 2×78278477² = 12255039922879058, which contains 22 as substring.

Together with 78278479, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78278479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39139238 + 39139239.

It is an arithmetic number, because the mean of its divisors is an integer number (39139239).

Almost surely, 2^78278477 is an apocalyptic number.

It is an amenable number.

78278477 is a deficient number, since it is larger than the sum of its proper divisors (1).

78278477 is an equidigital number, since it uses as much as digits as its factorization.

78278477 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1229312, while the sum is 50.

The square root of 78278477 is about 8847.5124752667. The cubic root of 78278477 is about 427.7737416659.

The spelling of 78278477 in words is "seventy-eight million, two hundred seventy-eight thousand, four hundred seventy-seven".