21028320000557 has 2 divisors, whose sum is σ = 21028320000558. Its totient is φ = 21028320000556.

The previous prime is 21028320000529. The next prime is 21028320000601. The reversal of 21028320000557 is 75500002382012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13898960753161 + 7129359247396 = 3728131^2 + 2670086^2 .

It is a cyclic number.

It is not a de Polignac number, because 21028320000557 - 2²⁴ = 21028303223341 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21028320000157) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10514160000278 + 10514160000279.

It is an arithmetic number, because the mean of its divisors is an integer number (10514160000279).

Almost surely, 2^{21028320000557} is an apocalyptic number.

It is an amenable number.

21028320000557 is a deficient number, since it is larger than the sum of its proper divisors (1).

21028320000557 is an equidigital number, since it uses as much as digits as its factorization.

21028320000557 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 33600, while the sum is 35.

Adding to 21028320000557 its reverse (75500002382012), we get a palindrome (96528322382569).

The spelling of 21028320000557 in words is "twenty-one trillion, twenty-eight billion, three hundred twenty million, five hundred fifty-seven", and thus it is an aban number.