8538721 has 2 divisors, whose sum is σ = 8538722. Its totient is φ = 8538720.

The previous prime is 8538713. The next prime is 8538767. The reversal of 8538721 is 1278358.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8526400 + 12321 = 2920^2 + 111^2 .

It is a cyclic number.

It is not a de Polignac number, because 8538721 - 2³ = 8538713 is a prime.

It is not a weakly prime, because it can be changed into another prime (8538781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4269360 + 4269361.

It is an arithmetic number, because the mean of its divisors is an integer number (4269361).

Almost surely, 2^8538721 is an apocalyptic number.

It is an amenable number.

8538721 is a deficient number, since it is larger than the sum of its proper divisors (1).

8538721 is an equidigital number, since it uses as much as digits as its factorization.

8538721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13440, while the sum is 34.

The square root of 8538721 is about 2922.1089986515. The cubic root of 8538721 is about 204.3921793799.

The spelling of 8538721 in words is "eight million, five hundred thirty-eight thousand, seven hundred twenty-one".