78604021 has 8 divisors (see below), whose sum is σ = 81089720. Its totient is φ = 76137408.

The previous prime is 78603997. The next prime is 78604027. The reversal of 78604021 is 12040687.

It can be written as a sum of positive squares in 4 ways, for example, as 59367025 + 19236996 = 7705^2 + 4386^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 78604021 - 2⁹ = 78603509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78604027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3835 + ... + 13111.

It is an arithmetic number, because the mean of its divisors is an integer number (10136215).

Almost surely, 2^78604021 is an apocalyptic number.

It is an amenable number.

78604021 is a deficient number, since it is larger than the sum of its proper divisors (2485699).

78604021 is a wasteful number, since it uses less digits than its factorization.

78604021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9543.

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 78604021 is about 8865.8908745822. The cubic root of 78604021 is about 428.3659290080.

It can be divided in two parts, 7860 and 4021, that added together give a square (11881 = 109²).

The spelling of 78604021 in words is "seventy-eight million, six hundred four thousand, twenty-one".