6666721722 has 24 divisors (see below), whose sum is σ = 14449829940. Its totient is φ = 2221430400.

The previous prime is 6666721693. The next prime is 6666721739. The reversal of 6666721722 is 2271276666.

6666721722 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 6457890321 + 208831401 = 80361^2 + 14451^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15697 + ... + 116532.

Almost surely, 2^6666721722 is an apocalyptic number.

6666721722 is an abundant number, since it is smaller than the sum of its proper divisors (7783108218).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6666721722 is a wasteful number, since it uses less digits than its factorization.

6666721722 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135038 (or 135035 counting only the distinct ones).

The product of its digits is 508032, while the sum is 45.

The square root of 6666721722 is about 81649.9952357623. The cubic root of 6666721722 is about 1882.0772386530.

The spelling of 6666721722 in words is "six billion, six hundred sixty-six million, seven hundred twenty-one thousand, seven hundred twenty-two".