8320720618121 has 4 divisors (see below), whose sum is σ = 8461749781200. Its totient is φ = 8179691455044.

The previous prime is 8320720618099. The next prime is 8320720618141. The reversal of 8320720618121 is 1218160270238.

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 a cyclic number.

It is not a de Polignac number, because 8320720618121 - 2¹⁴ = 8320720601737 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 (8320720618141) 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, 70514581451 + ... + 70514581568.

It is an arithmetic number, because the mean of its divisors is an integer number (2115437445300).

Almost surely, 2^{8320720618121} is an apocalyptic number.

It is an amenable number.

8320720618121 is a deficient number, since it is larger than the sum of its proper divisors (141029163079).

8320720618121 is a wasteful number, since it uses less digits than its factorization.

8320720618121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141029163078.

The product of its (nonzero) digits is 64512, while the sum is 41.

Adding to 8320720618121 its reverse (1218160270238), we get a palindrome (9538880888359).

The spelling of 8320720618121 in words is "eight trillion, three hundred twenty billion, seven hundred twenty million, six hundred eighteen thousand, one hundred twenty-one".