3193728721 has 2 divisors, whose sum is σ = 3193728722. Its totient is φ = 3193728720.

The previous prime is 3193728673. The next prime is 3193728781. The reversal of 3193728721 is 1278273913.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1622478400 + 1571250321 = 40280^2 + 39639^2 .

It is a cyclic number.

It is not a de Polignac number, because 3193728721 - 2²³ = 3185340113 is a prime.

It is not a weakly prime, because it can be changed into another prime (3193728781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1596864360 + 1596864361.

It is an arithmetic number, because the mean of its divisors is an integer number (1596864361).

Almost surely, 2^3193728721 is an apocalyptic number.

It is an amenable number.

3193728721 is a deficient number, since it is larger than the sum of its proper divisors (1).

3193728721 is an equidigital number, since it uses as much as digits as its factorization.

3193728721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 127008, while the sum is 43.

The square root of 3193728721 is about 56513.0845114651. The cubic root of 3193728721 is about 1472.6493203546.

The spelling of 3193728721 in words is "three billion, one hundred ninety-three million, seven hundred twenty-eight thousand, seven hundred twenty-one".