255121635521 has 2 divisors, whose sum is σ = 255121635522. Its totient is φ = 255121635520.

The previous prime is 255121635403. The next prime is 255121635553. The reversal of 255121635521 is 125536121552.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 148101055921 + 107020579600 = 384839^2 + 327140^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-255121635521 is a prime.

It is not a weakly prime, because it can be changed into another prime (255121635581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 127560817760 + 127560817761.

It is an arithmetic number, because the mean of its divisors is an integer number (127560817761).

Almost surely, 2^255121635521 is an apocalyptic number.

It is an amenable number.

255121635521 is a deficient number, since it is larger than the sum of its proper divisors (1).

255121635521 is an equidigital number, since it uses as much as digits as its factorization.

255121635521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90000, while the sum is 38.

The spelling of 255121635521 in words is "two hundred fifty-five billion, one hundred twenty-one million, six hundred thirty-five thousand, five hundred twenty-one".