78449217 has 32 divisors (see below), whose sum is σ = 131066880. Its totient is φ = 40547520.

The previous prime is 78449209. The next prime is 78449221. The reversal of 78449217 is 71294487.

It is a happy number.

It is not a de Polignac number, because 78449217 - 2³ = 78449209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78449227) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 52158 + ... + 53640.

It is an arithmetic number, because the mean of its divisors is an integer number (4095840).

Almost surely, 2^78449217 is an apocalyptic number.

78449217 is a gapful number since it is divisible by the number (77) formed by its first and last digit.

It is an amenable number.

78449217 is a deficient number, since it is larger than the sum of its proper divisors (52617663).

78449217 is a wasteful number, since it uses less digits than its factorization.

78449217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1733.

The product of its digits is 112896, while the sum is 42.

The square root of 78449217 is about 8857.1562592065. The cubic root of 78449217 is about 428.0845339912.

The spelling of 78449217 in words is "seventy-eight million, four hundred forty-nine thousand, two hundred seventeen".