7997121809 has 8 divisors (see below), whose sum is σ = 8396362560. Its totient is φ = 7606112976.

The previous prime is 7997121787. The next prime is 7997121841. The reversal of 7997121809 is 9081217997.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 7997121809 - 2³² = 3702154513 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (7997124809) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2055989 + ... + 2059874.

It is an arithmetic number, because the mean of its divisors is an integer number (1049545320).

Almost surely, 2^7997121809 is an apocalyptic number.

It is an amenable number.

7997121809 is a deficient number, since it is larger than the sum of its proper divisors (399240751).

7997121809 is a wasteful number, since it uses less digits than its factorization.

7997121809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4115959.

The product of its (nonzero) digits is 571536, while the sum is 53.

The square root of 7997121809 is about 89426.6280757583. The cubic root of 7997121809 is about 1999.7601219804.

The spelling of 7997121809 in words is "seven billion, nine hundred ninety-seven million, one hundred twenty-one thousand, eight hundred nine".