6556011662821 has 2 divisors, whose sum is σ = 6556011662822. Its totient is φ = 6556011662820.

The previous prime is 6556011662663. The next prime is 6556011662857. The reversal of 6556011662821 is 1282661106556.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4439073961921 + 2116937700900 = 2106911^2 + 1454970^2 .

It is a cyclic number.

It is not a de Polignac number, because 6556011662821 - 2²³ = 6556003274213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6556011162821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3278005831410 + 3278005831411.

It is an arithmetic number, because the mean of its divisors is an integer number (3278005831411).

Almost surely, 2^{6556011662821} is an apocalyptic number.

It is an amenable number.

6556011662821 is a deficient number, since it is larger than the sum of its proper divisors (1).

6556011662821 is an equidigital number, since it uses as much as digits as its factorization.

6556011662821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1036800, while the sum is 49.

The spelling of 6556011662821 in words is "six trillion, five hundred fifty-six billion, eleven million, six hundred sixty-two thousand, eight hundred twenty-one".