3213721 has 8 divisors (see below), whose sum is σ = 3832704. Its totient is φ = 2634720.

The previous prime is 3213689. The next prime is 3213737. The reversal of 3213721 is 1273123.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 3213721 - 2⁵ = 3213689 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3213421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9820 + ... + 10141.

It is an arithmetic number, because the mean of its divisors is an integer number (479088).

Almost surely, 2^3213721 is an apocalyptic number.

It is an amenable number.

3213721 is a deficient number, since it is larger than the sum of its proper divisors (618983).

3213721 is a wasteful number, since it uses less digits than its factorization.

3213721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19991.

The product of its digits is 252, while the sum is 19.

The square root of 3213721 is about 1792.6854157939. The cubic root of 3213721 is about 147.5715787797.

Adding to 3213721 its reverse (1273123), we get a palindrome (4486844).

The spelling of 3213721 in words is "three million, two hundred thirteen thousand, seven hundred twenty-one".