3213618721 has 4 divisors (see below), whose sum is σ = 3226123332. Its totient is φ = 3201114112.

The previous prime is 3213618691. The next prime is 3213618743. The reversal of 3213618721 is 1278163123.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1278163123 = 941 ⋅1358303.

It can be written as a sum of positive squares in 2 ways, for example, as 1926244321 + 1287374400 = 43889^2 + 35880^2 .

It is a cyclic number.

It is not a de Polignac number, because 3213618721 - 2¹¹ = 3213616673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3213618781) 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 in 3 ways as a sum of consecutive naturals, for example, 6251920 + ... + 6252433.

It is an arithmetic number, because the mean of its divisors is an integer number (806530833).

Almost surely, 2^3213618721 is an apocalyptic number.

It is an amenable number.

3213618721 is a deficient number, since it is larger than the sum of its proper divisors (12504611).

3213618721 is a wasteful number, since it uses less digits than its factorization.

3213618721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12504610.

The product of its digits is 12096, while the sum is 34.

The square root of 3213618721 is about 56688.7883183262. The cubic root of 3213618721 is about 1475.7001323890.

The spelling of 3213618721 in words is "three billion, two hundred thirteen million, six hundred eighteen thousand, seven hundred twenty-one".