3221965721 has 4 divisors (see below), whose sum is σ = 3469809252. Its totient is φ = 2974122192.

The previous prime is 3221965711. The next prime is 3221965777. The reversal of 3221965721 is 1275691223.

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 1969584400 + 1252381321 = 44380^2 + 35389^2 .

It is a cyclic number.

It is not a de Polignac number, because 3221965721 - 2²⁶ = 3154856857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (3221965711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 123921746 + ... + 123921771.

It is an arithmetic number, because the mean of its divisors is an integer number (867452313).

Almost surely, 2^3221965721 is an apocalyptic number.

It is an amenable number.

3221965721 is a deficient number, since it is larger than the sum of its proper divisors (247843531).

3221965721 is a wasteful number, since it uses less digits than its factorization.

3221965721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 247843530.

The product of its digits is 45360, while the sum is 38.

The square root of 3221965721 is about 56762.3618342296. The cubic root of 3221965721 is about 1476.9766808189.

The spelling of 3221965721 in words is "three billion, two hundred twenty-one million, nine hundred sixty-five thousand, seven hundred twenty-one".