8121251389 has 2 divisors, whose sum is σ = 8121251390. Its totient is φ = 8121251388.

The previous prime is 8121251363. The next prime is 8121251477. The reversal of 8121251389 is 9831521218.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7547265625 + 573985764 = 86875^2 + 23958^2 .

It is a cyclic number.

It is not a de Polignac number, because 8121251389 - 2⁵ = 8121251357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8121252389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4060625694 + 4060625695.

It is an arithmetic number, because the mean of its divisors is an integer number (4060625695).

Almost surely, 2^8121251389 is an apocalyptic number.

It is an amenable number.

8121251389 is a deficient number, since it is larger than the sum of its proper divisors (1).

8121251389 is an equidigital number, since it uses as much as digits as its factorization.

8121251389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34560, while the sum is 40.

The square root of 8121251389 is about 90117.9859351062. The cubic root of 8121251389 is about 2010.0536596980.

The spelling of 8121251389 in words is "eight billion, one hundred twenty-one million, two hundred fifty-one thousand, three hundred eighty-nine".