8157521 has 2 divisors, whose sum is σ = 8157522. Its totient is φ = 8157520.

The previous prime is 8157509. The next prime is 8157533. The reversal of 8157521 is 1257518.

It is a balanced prime because it is at equal distance from previous prime (8157509) and next prime (8157533).

It can be written as a sum of positive squares in only one way, i.e., 4157521 + 4000000 = 2039^2 + 2000^2 .

It is a cyclic number.

It is not a de Polignac number, because 8157521 - 2¹⁰ = 8156497 is a prime.

It is a Chen prime.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (8157581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4078760 + 4078761.

It is an arithmetic number, because the mean of its divisors is an integer number (4078761).

Almost surely, 2^8157521 is an apocalyptic number.

It is an amenable number.

8157521 is a deficient number, since it is larger than the sum of its proper divisors (1).

8157521 is an equidigital number, since it uses as much as digits as its factorization.

8157521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2800, while the sum is 29.

The square root of 8157521 is about 2856.1374266656. The cubic root of 8157521 is about 201.3041524476.

The spelling of 8157521 in words is "eight million, one hundred fifty-seven thousand, five hundred twenty-one".