78417289 has 2 divisors, whose sum is σ = 78417290. Its totient is φ = 78417288.

The previous prime is 78417223. The next prime is 78417307. The reversal of 78417289 is 98271487.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65885689 + 12531600 = 8117^2 + 3540^2 .

It is a cyclic number.

It is not a de Polignac number, because 78417289 - 2¹⁵ = 78384521 is a prime.

It is a super-2 number, since 2×78417289² = 12298542428219042, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78412289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39208644 + 39208645.

It is an arithmetic number, because the mean of its divisors is an integer number (39208645).

Almost surely, 2^78417289 is an apocalyptic number.

It is an amenable number.

78417289 is a deficient number, since it is larger than the sum of its proper divisors (1).

78417289 is an equidigital number, since it uses as much as digits as its factorization.

78417289 is an evil number, because the sum of its binary digits is even.

The product of its digits is 225792, while the sum is 46.

The square root of 78417289 is about 8855.3536914118. The cubic root of 78417289 is about 428.0264508211.

The spelling of 78417289 in words is "seventy-eight million, four hundred seventeen thousand, two hundred eighty-nine".