3215721121 has 4 divisors (see below), whose sum is σ = 3215870100. Its totient is φ = 3215572144.

The previous prime is 3215721077. The next prime is 3215721133. The reversal of 3215721121 is 1211275123.

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 2992637025 + 223084096 = 54705^2 + 14936^2 .

It is a cyclic number.

It is not a de Polignac number, because 3215721121 - 2¹⁵ = 3215688353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3215721721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35206 + ... + 87583.

It is an arithmetic number, because the mean of its divisors is an integer number (803967525).

Almost surely, 2^3215721121 is an apocalyptic number.

It is an amenable number.

3215721121 is a deficient number, since it is larger than the sum of its proper divisors (148979).

3215721121 is a wasteful number, since it uses less digits than its factorization.

3215721121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 148978.

The product of its digits is 840, while the sum is 25.

The square root of 3215721121 is about 56707.3286357240. The cubic root of 3215721121 is about 1476.0218709961.

Adding to 3215721121 its reverse (1211275123), we get a palindrome (4426996244).

The spelling of 3215721121 in words is "three billion, two hundred fifteen million, seven hundred twenty-one thousand, one hundred twenty-one".