3215918561 has 4 divisors (see below), whose sum is σ = 3220844052. Its totient is φ = 3210993072.

The previous prime is 3215918557. The next prime is 3215918591. The reversal of 3215918561 is 1658195123.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1658195123 = 13 ⋅127553471.

It can be written as a sum of positive squares in 2 ways, for example, as 1523418961 + 1692499600 = 39031^2 + 41140^2 .

It is a cyclic number.

It is not a de Polignac number, because 3215918561 - 2² = 3215918557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3215918521) 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, 2461766 + ... + 2463071.

It is an arithmetic number, because the mean of its divisors is an integer number (805211013).

Almost surely, 2^3215918561 is an apocalyptic number.

It is an amenable number.

3215918561 is a deficient number, since it is larger than the sum of its proper divisors (4925491).

3215918561 is an equidigital number, since it uses as much as digits as its factorization.

3215918561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4925490.

The product of its digits is 64800, while the sum is 41.

The square root of 3215918561 is about 56709.0694774654. The cubic root of 3215918561 is about 1476.0520788182.

The spelling of 3215918561 in words is "three billion, two hundred fifteen million, nine hundred eighteen thousand, five hundred sixty-one".