6446969721 has 24 divisors (see below), whose sum is σ = 9879948000. Its totient is φ = 4037003136.

The previous prime is 6446969689. The next prime is 6446969773. The reversal of 6446969721 is 1279696446.

It is a happy number.

6446969721 is a `hidden beast` number, since 6 + 446 + 96 + 97 + 21 = 666.

It is not a de Polignac number, because 6446969721 - 2⁵ = 6446969689 is a prime.

It is not an unprimeable number, because it can be changed into a prime (6446969521) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 34126 + ... + 118568.

It is an arithmetic number, because the mean of its divisors is an integer number (411664500).

Almost surely, 2^6446969721 is an apocalyptic number.

It is an amenable number.

6446969721 is a deficient number, since it is larger than the sum of its proper divisors (3432978279).

6446969721 is a wasteful number, since it uses less digits than its factorization.

6446969721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84965 (or 84962 counting only the distinct ones).

The product of its digits is 3919104, while the sum is 54.

The square root of 6446969721 is about 80293.0241116873. The cubic root of 6446969721 is about 1861.1664284421.

The spelling of 6446969721 in words is "six billion, four hundred forty-six million, nine hundred sixty-nine thousand, seven hundred twenty-one".