2551021155521 has 2 divisors, whose sum is σ = 2551021155522. Its totient is φ = 2551021155520.

The previous prime is 2551021155461. The next prime is 2551021155559. The reversal of 2551021155521 is 1255511201552.

2551021155521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2343348640000 + 207672515521 = 1530800^2 + 455711^2 .

It is a cyclic number.

It is not a de Polignac number, because 2551021155521 - 2¹⁴ = 2551021139137 is a prime.

It is not a weakly prime, because it can be changed into another prime (2551021155581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1275510577760 + 1275510577761.

It is an arithmetic number, because the mean of its divisors is an integer number (1275510577761).

Almost surely, 2^{2551021155521} is an apocalyptic number.

It is an amenable number.

2551021155521 is a deficient number, since it is larger than the sum of its proper divisors (1).

2551021155521 is an equidigital number, since it uses as much as digits as its factorization.

2551021155521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25000, while the sum is 35.

The spelling of 2551021155521 in words is "two trillion, five hundred fifty-one billion, twenty-one million, one hundred fifty-five thousand, five hundred twenty-one".