8125553621 has 2 divisors, whose sum is σ = 8125553622. Its totient is φ = 8125553620.

The previous prime is 8125553549. The next prime is 8125553651. The reversal of 8125553621 is 1263555218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7427854225 + 697699396 = 86185^2 + 26414^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8125553621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8125553651) 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 as a sum of consecutive naturals, namely, 4062776810 + 4062776811.

It is an arithmetic number, because the mean of its divisors is an integer number (4062776811).

Almost surely, 2^8125553621 is an apocalyptic number.

It is an amenable number.

8125553621 is a deficient number, since it is larger than the sum of its proper divisors (1).

8125553621 is an equidigital number, since it uses as much as digits as its factorization.

8125553621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72000, while the sum is 38.

The square root of 8125553621 is about 90141.8527710630. The cubic root of 8125553621 is about 2010.4085389388.

The spelling of 8125553621 in words is "eight billion, one hundred twenty-five million, five hundred fifty-three thousand, six hundred twenty-one".