6631321913 has 4 divisors (see below), whose sum is σ = 6657124980. Its totient is φ = 6605518848.

The previous prime is 6631321861. The next prime is 6631321951. The reversal of 6631321913 is 3191231366.

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 6382092544 + 249229369 = 79888^2 + 15787^2 .

It is a cyclic number.

It is not a de Polignac number, because 6631321913 - 2⁶ = 6631321849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6631321313) 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, 12901148 + ... + 12901661.

It is an arithmetic number, because the mean of its divisors is an integer number (1664281245).

Almost surely, 2^6631321913 is an apocalyptic number.

It is an amenable number.

6631321913 is a deficient number, since it is larger than the sum of its proper divisors (25803067).

6631321913 is a wasteful number, since it uses less digits than its factorization.

6631321913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25803066.

The product of its digits is 17496, while the sum is 35.

The square root of 6631321913 is about 81432.9289231328. The cubic root of 6631321913 is about 1878.7400937706.

The spelling of 6631321913 in words is "six billion, six hundred thirty-one million, three hundred twenty-one thousand, nine hundred thirteen".