8020997561 has 4 divisors (see below), whose sum is σ = 8207532432. Its totient is φ = 7834462692.

The previous prime is 8020997531. The next prime is 8020997591. The reversal of 8020997561 is 1657990208.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (8020997531) and next prime (8020997591).

It is a cyclic number.

It is not a de Polignac number, because 8020997561 - 2¹⁸ = 8020735417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8020997521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 93267371 + ... + 93267456.

It is an arithmetic number, because the mean of its divisors is an integer number (2051883108).

Almost surely, 2^8020997561 is an apocalyptic number.

It is an amenable number.

8020997561 is a deficient number, since it is larger than the sum of its proper divisors (186534871).

8020997561 is a wasteful number, since it uses less digits than its factorization.

8020997561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 186534870.

The product of its (nonzero) digits is 272160, while the sum is 47.

The square root of 8020997561 is about 89560.0221136641. The cubic root of 8020997561 is about 2001.7482680841.

The spelling of 8020997561 in words is "eight billion, twenty million, nine hundred ninety-seven thousand, five hundred sixty-one".