5220721721 has 4 divisors (see below), whose sum is σ = 5220914832. Its totient is φ = 5220528612.

The previous prime is 5220721717. The next prime is 5220721747. The reversal of 5220721721 is 1271270225.

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 5220721721 - 2² = 5220721717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (5220721421) 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, 47795 + ... + 112808.

It is an arithmetic number, because the mean of its divisors is an integer number (1305228708).

Almost surely, 2^5220721721 is an apocalyptic number.

It is an amenable number.

5220721721 is a deficient number, since it is larger than the sum of its proper divisors (193111).

5220721721 is a wasteful number, since it uses less digits than its factorization.

5220721721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193110.

The product of its (nonzero) digits is 3920, while the sum is 29.

The square root of 5220721721 is about 72254.5619390222. The cubic root of 5220721721 is about 1734.7764381805.

Adding to 5220721721 its reverse (1271270225), we get a palindrome (6491991946).

The spelling of 5220721721 in words is "five billion, two hundred twenty million, seven hundred twenty-one thousand, seven hundred twenty-one".