78734774221 has 4 divisors (see below), whose sum is σ = 78769476700. Its totient is φ = 78700071744.

The previous prime is 78734774203. The next prime is 78734774231. The reversal of 78734774221 is 12247743787.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5988592996 + 72746181225 = 77386^2 + 269715^2 .

It is a cyclic number.

It is not a de Polignac number, because 78734774221 - 2³¹ = 76587290573 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 (78734774231) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17347836 + ... + 17352373.

It is an arithmetic number, because the mean of its divisors is an integer number (19692369175).

Almost surely, 2^78734774221 is an apocalyptic number.

It is an amenable number.

78734774221 is a deficient number, since it is larger than the sum of its proper divisors (34702479).

78734774221 is a wasteful number, since it uses less digits than its factorization.

78734774221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34702478.

The product of its digits is 3687936, while the sum is 52.

The spelling of 78734774221 in words is "seventy-eight billion, seven hundred thirty-four million, seven hundred seventy-four thousand, two hundred twenty-one".