8257385621 has 2 divisors, whose sum is σ = 8257385622. Its totient is φ = 8257385620.

The previous prime is 8257385581. The next prime is 8257385627. The reversal of 8257385621 is 1265837528.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7976990596 + 280395025 = 89314^2 + 16745^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8257385621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8257385627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4128692810 + 4128692811.

It is an arithmetic number, because the mean of its divisors is an integer number (4128692811).

Almost surely, 2^8257385621 is an apocalyptic number.

It is an amenable number.

8257385621 is a deficient number, since it is larger than the sum of its proper divisors (1).

8257385621 is an equidigital number, since it uses as much as digits as its factorization.

8257385621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 806400, while the sum is 47.

The square root of 8257385621 is about 90870.1580333170. The cubic root of 8257385621 is about 2021.2228015224. Note that the first 3 decimals are identical.

The spelling of 8257385621 in words is "eight billion, two hundred fifty-seven million, three hundred eighty-five thousand, six hundred twenty-one".