7216616721 has 4 divisors (see below), whose sum is σ = 9622155632. Its totient is φ = 4811077812.

The previous prime is 7216616717. The next prime is 7216616731. The reversal of 7216616721 is 1276166127.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1276166127 = 3 ⋅425388709.

It is not a de Polignac number, because 7216616721 - 2² = 7216616717 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 7216616721.

It is not an unprimeable number, because it can be changed into a prime (7216616731) 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, 1202769451 + ... + 1202769456.

It is an arithmetic number, because the mean of its divisors is an integer number (2405538908).

Almost surely, 2^7216616721 is an apocalyptic number.

It is an amenable number.

7216616721 is a deficient number, since it is larger than the sum of its proper divisors (2405538911).

7216616721 is a wasteful number, since it uses less digits than its factorization.

7216616721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2405538910.

The product of its digits is 42336, while the sum is 39.

The square root of 7216616721 is about 84950.6722810361. The cubic root of 7216616721 is about 1932.4631156524.

The spelling of 7216616721 in words is "seven billion, two hundred sixteen million, six hundred sixteen thousand, seven hundred twenty-one".