7211016721 has 4 divisors (see below), whose sum is σ = 7459672500. Its totient is φ = 6962360944.

The previous prime is 7211016679. The next prime is 7211016731. The reversal of 7211016721 is 1276101127.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5785123600 + 1425893121 = 76060^2 + 37761^2 .

It is a cyclic number.

It is not a de Polignac number, because 7211016721 - 2¹¹ = 7211014673 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 7211016721.

It is not an unprimeable number, because it can be changed into a prime (7211016731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 124327846 + ... + 124327903.

It is an arithmetic number, because the mean of its divisors is an integer number (1864918125).

Almost surely, 2^7211016721 is an apocalyptic number.

It is an amenable number.

7211016721 is a deficient number, since it is larger than the sum of its proper divisors (248655779).

7211016721 is a wasteful number, since it uses less digits than its factorization.

7211016721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248655778.

The product of its (nonzero) digits is 1176, while the sum is 28.

The square root of 7211016721 is about 84917.7055801674. The cubic root of 7211016721 is about 1931.9631309521.

Adding to 7211016721 its reverse (1276101127), we get a palindrome (8487117848).

It can be divided in two parts, 72110 and 16721, that added together give a triangular number (88831 = T₄₂₁).

The spelling of 7211016721 in words is "seven billion, two hundred eleven million, sixteen thousand, seven hundred twenty-one".