78600721 has 4 divisors (see below), whose sum is σ = 79071552. Its totient is φ = 78129892.

The previous prime is 78600713. The next prime is 78600737. The reversal of 78600721 is 12700687.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 78600721 - 2³ = 78600713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78606721) 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, 235165 + ... + 235498.

It is an arithmetic number, because the mean of its divisors is an integer number (19767888).

Almost surely, 2^78600721 is an apocalyptic number.

It is an amenable number.

78600721 is a deficient number, since it is larger than the sum of its proper divisors (470831).

78600721 is a wasteful number, since it uses less digits than its factorization.

78600721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 470830.

The product of its (nonzero) digits is 4704, while the sum is 31.

The square root of 78600721 is about 8865.7047661198. The cubic root of 78600721 is about 428.3599342878.

The spelling of 78600721 in words is "seventy-eight million, six hundred thousand, seven hundred twenty-one".