8409250021 has 2 divisors, whose sum is σ = 8409250022. Its totient is φ = 8409250020.

The previous prime is 8409249991. The next prime is 8409250027. The reversal of 8409250021 is 1200529048.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7354949121 + 1054300900 = 85761^2 + 32470^2 .

It is a cyclic number.

It is not a de Polignac number, because 8409250021 - 2¹³ = 8409241829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8409250027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4204625010 + 4204625011.

It is an arithmetic number, because the mean of its divisors is an integer number (4204625011).

Almost surely, 2^8409250021 is an apocalyptic number.

It is an amenable number.

8409250021 is a deficient number, since it is larger than the sum of its proper divisors (1).

8409250021 is an equidigital number, since it uses as much as digits as its factorization.

8409250021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 8409250021 is about 91701.9630160663. The cubic root of 8409250021 is about 2033.5386055924.

Adding to 8409250021 its reverse (1200529048), we get a palindrome (9609779069).

The spelling of 8409250021 in words is "eight billion, four hundred nine million, two hundred fifty thousand, twenty-one".