8155688621 has 2 divisors, whose sum is σ = 8155688622. Its totient is φ = 8155688620.

The previous prime is 8155688587. The next prime is 8155688663. The reversal of 8155688621 is 1268865518.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8120713225 + 34975396 = 90115^2 + 5914^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8155688621 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 8155688621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8155688221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4077844310 + 4077844311.

It is an arithmetic number, because the mean of its divisors is an integer number (4077844311).

Almost surely, 2^8155688621 is an apocalyptic number.

It is an amenable number.

8155688621 is a deficient number, since it is larger than the sum of its proper divisors (1).

8155688621 is an equidigital number, since it uses as much as digits as its factorization.

8155688621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 921600, while the sum is 50.

The square root of 8155688621 is about 90308.8512882320. The cubic root of 8155688621 is about 2012.8907870469.

The spelling of 8155688621 in words is "eight billion, one hundred fifty-five million, six hundred eighty-eight thousand, six hundred twenty-one".