6639137060921 has 2 divisors, whose sum is σ = 6639137060922. Its totient is φ = 6639137060920.

The previous prime is 6639137060827. The next prime is 6639137060929. The reversal of 6639137060921 is 1290607319366.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4211274475321 + 2427862585600 = 2052139^2 + 1558160^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6639137060921 is a prime.

It is not a weakly prime, because it can be changed into another prime (6639137060929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3319568530460 + 3319568530461.

It is an arithmetic number, because the mean of its divisors is an integer number (3319568530461).

Almost surely, 2^{6639137060921} is an apocalyptic number.

It is an amenable number.

6639137060921 is a deficient number, since it is larger than the sum of its proper divisors (1).

6639137060921 is an equidigital number, since it uses as much as digits as its factorization.

6639137060921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2204496, while the sum is 53.

The spelling of 6639137060921 in words is "six trillion, six hundred thirty-nine billion, one hundred thirty-seven million, sixty thousand, nine hundred twenty-one".