6909684721 has 2 divisors, whose sum is σ = 6909684722. Its totient is φ = 6909684720.

The previous prime is 6909684709. The next prime is 6909684757. The reversal of 6909684721 is 1274869096.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3704426496 + 3205258225 = 60864^2 + 56615^2 .

It is a cyclic number.

It is not a de Polignac number, because 6909684721 - 2¹⁵ = 6909651953 is a prime.

It is not a weakly prime, because it can be changed into another prime (6909684791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3454842360 + 3454842361.

It is an arithmetic number, because the mean of its divisors is an integer number (3454842361).

Almost surely, 2^6909684721 is an apocalyptic number.

It is an amenable number.

6909684721 is a deficient number, since it is larger than the sum of its proper divisors (1).

6909684721 is an equidigital number, since it uses as much as digits as its factorization.

6909684721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1306368, while the sum is 52.

The square root of 6909684721 is about 83124.5133579740. The cubic root of 6909684721 is about 1904.6685490077.

The spelling of 6909684721 in words is "six billion, nine hundred nine million, six hundred eighty-four thousand, seven hundred twenty-one".