78447213 has 12 divisors (see below), whose sum is σ = 122029180. Its totient is φ = 48275136.

The previous prime is 78447137. The next prime is 78447221. The reversal of 78447213 is 31274487.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 26347689 + 52099524 = 5133^2 + 7218^2 .

It is not a de Polignac number, because 78447213 - 2²¹ = 76350061 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78447223) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 335128 + ... + 335361.

Almost surely, 2^78447213 is an apocalyptic number.

It is an amenable number.

78447213 is a deficient number, since it is larger than the sum of its proper divisors (43581967).

78447213 is a wasteful number, since it uses less digits than its factorization.

78447213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 670508 (or 670505 counting only the distinct ones).

The product of its digits is 37632, while the sum is 36.

The square root of 78447213 is about 8857.0431296229. The cubic root of 78447213 is about 428.0808887935.

The spelling of 78447213 in words is "seventy-eight million, four hundred forty-seven thousand, two hundred thirteen".