78789121636 has 27 divisors (see below), whose sum is σ = 138642592921. Its totient is φ = 39178145744.

The previous prime is 78789121589. The next prime is 78789121637. The reversal of 78789121636 is 63612198787.

The square root of 78789121636 is 280694.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 74545380900 + 4243740736 = 273030^2 + 65144^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78789121637) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 164486445 + ... + 164486923.

Almost surely, 2^78789121636 is an apocalyptic number.

78789121636 is the 280694-th square number.

It is an amenable number.

78789121636 is a deficient number, since it is larger than the sum of its proper divisors (59853471285).

78789121636 is an frugal number, since it uses more digits than its factorization.

78789121636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1548 (or 774 counting only the distinct ones).

The product of its digits is 6096384, while the sum is 58.

The spelling of 78789121636 in words is "seventy-eight billion, seven hundred eighty-nine million, one hundred twenty-one thousand, six hundred thirty-six".