8020997521 has 2 divisors, whose sum is σ = 8020997522. Its totient is φ = 8020997520.

The previous prime is 8020997507. The next prime is 8020997531. The reversal of 8020997521 is 1257990208.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7575787521 + 445210000 = 87039^2 + 21100^2 .

It is a cyclic number.

It is not a de Polignac number, because 8020997521 - 2⁵ = 8020997489 is a prime.

It is not a weakly prime, because it can be changed into another prime (8020997531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4010498760 + 4010498761.

It is an arithmetic number, because the mean of its divisors is an integer number (4010498761).

Almost surely, 2^8020997521 is an apocalyptic number.

It is an amenable number.

8020997521 is a deficient number, since it is larger than the sum of its proper divisors (1).

8020997521 is an equidigital number, since it uses as much as digits as its factorization.

8020997521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 90720, while the sum is 43.

The square root of 8020997521 is about 89560.0218903502. The cubic root of 8020997521 is about 2001.7482647565.

The spelling of 8020997521 in words is "eight billion, twenty million, nine hundred ninety-seven thousand, five hundred twenty-one".