6538923821 has 2 divisors, whose sum is σ = 6538923822. Its totient is φ = 6538923820.

The previous prime is 6538923817. The next prime is 6538923847. The reversal of 6538923821 is 1283298356.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6538501321 + 422500 = 80861^2 + 650^2 .

It is a cyclic number.

It is not a de Polignac number, because 6538923821 - 2² = 6538923817 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6538928821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3269461910 + 3269461911.

It is an arithmetic number, because the mean of its divisors is an integer number (3269461911).

Almost surely, 2^6538923821 is an apocalyptic number.

It is an amenable number.

6538923821 is a deficient number, since it is larger than the sum of its proper divisors (1).

6538923821 is an equidigital number, since it uses as much as digits as its factorization.

6538923821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 622080, while the sum is 47.

The square root of 6538923821 is about 80863.6124656820. The cubic root of 6538923821 is about 1869.9733875744.

The spelling of 6538923821 in words is "six billion, five hundred thirty-eight million, nine hundred twenty-three thousand, eight hundred twenty-one".