6538707621 has 12 divisors (see below), whose sum is σ = 9445659340. Its totient is φ = 4358741760.

The previous prime is 6538707611. The next prime is 6538707653. The reversal of 6538707621 is 1267078356.

It can be written as a sum of positive squares in 2 ways, for example, as 1294920225 + 5243787396 = 35985^2 + 72414^2 .

It is not a de Polignac number, because 6538707621 - 2⁷ = 6538707493 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 (6538707611) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 99195 + ... + 151383.

Almost surely, 2^6538707621 is an apocalyptic number.

It is an amenable number.

6538707621 is a deficient number, since it is larger than the sum of its proper divisors (2906951719).

6538707621 is a wasteful number, since it uses less digits than its factorization.

6538707621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66116 (or 66113 counting only the distinct ones).

The product of its (nonzero) digits is 423360, while the sum is 45.

The square root of 6538707621 is about 80862.2756357994. The cubic root of 6538707621 is about 1869.9527780310.

The spelling of 6538707621 in words is "six billion, five hundred thirty-eight million, seven hundred seven thousand, six hundred twenty-one".