78386657 has 2 divisors, whose sum is σ = 78386658. Its totient is φ = 78386656.

The previous prime is 78386653. The next prime is 78386663. The reversal of 78386657 is 75668387.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 72607441 + 5779216 = 8521^2 + 2404^2 .

It is a cyclic number.

It is not a de Polignac number, because 78386657 - 2² = 78386653 is a prime.

It is a super-2 number, since 2×78386657² = 12288935991271298, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78386653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39193328 + 39193329.

It is an arithmetic number, because the mean of its divisors is an integer number (39193329).

Almost surely, 2^78386657 is an apocalyptic number.

It is an amenable number.

78386657 is a deficient number, since it is larger than the sum of its proper divisors (1).

78386657 is an equidigital number, since it uses as much as digits as its factorization.

78386657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1693440, while the sum is 50.

The square root of 78386657 is about 8853.6239472885. The cubic root of 78386657 is about 427.9707105033.

The spelling of 78386657 in words is "seventy-eight million, three hundred eighty-six thousand, six hundred fifty-seven".