78472817 has 2 divisors, whose sum is σ = 78472818. Its totient is φ = 78472816.

The previous prime is 78472789. The next prime is 78472847. The reversal of 78472817 is 71827487.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 70627216 + 7845601 = 8404^2 + 2801^2 .

It is a cyclic number.

It is not a de Polignac number, because 78472817 - 2¹⁰ = 78471793 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78472847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39236408 + 39236409.

It is an arithmetic number, because the mean of its divisors is an integer number (39236409).

Almost surely, 2^78472817 is an apocalyptic number.

It is an amenable number.

78472817 is a deficient number, since it is larger than the sum of its proper divisors (1).

78472817 is an equidigital number, since it uses as much as digits as its factorization.

78472817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 175616, while the sum is 44.

The square root of 78472817 is about 8858.4884150740. The cubic root of 78472817 is about 428.1274567994.

The spelling of 78472817 in words is "seventy-eight million, four hundred seventy-two thousand, eight hundred seventeen".