78072217 has 4 divisors (see below), whose sum is σ = 79733376. Its totient is φ = 76411060.

The previous prime is 78072209. The next prime is 78072271. The reversal of 78072217 is 71227087.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 71227087 = 769 ⋅92623.

It is a cyclic number.

It is not a de Polignac number, because 78072217 - 2³ = 78072209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78072287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 830509 + ... + 830602.

It is an arithmetic number, because the mean of its divisors is an integer number (19933344).

Almost surely, 2^78072217 is an apocalyptic number.

It is an amenable number.

78072217 is a deficient number, since it is larger than the sum of its proper divisors (1661159).

78072217 is a wasteful number, since it uses less digits than its factorization.

78072217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1661158.

The product of its (nonzero) digits is 10976, while the sum is 34.

The square root of 78072217 is about 8835.8484029549. The cubic root of 78072217 is about 427.3976901415.

The spelling of 78072217 in words is "seventy-eight million, seventy-two thousand, two hundred seventeen".