256507724562121 has 2 divisors, whose sum is σ = 256507724562122. Its totient is φ = 256507724562120.

The previous prime is 256507724562073. The next prime is 256507724562137. The reversal of 256507724562121 is 121265427705652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 228587184810000 + 27920539752121 = 15119100^2 + 5283989^2 .

It is a cyclic number.

It is not a de Polignac number, because 256507724562121 - 2⁷ = 256507724561993 is a prime.

It is a super-2 number, since 2×256507724562121² (a number of 30 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (256507724562181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128253862281060 + 128253862281061.

It is an arithmetic number, because the mean of its divisors is an integer number (128253862281061).

Almost surely, 2^{256507724562121} is an apocalyptic number.

It is an amenable number.

256507724562121 is a deficient number, since it is larger than the sum of its proper divisors (1).

256507724562121 is an equidigital number, since it uses as much as digits as its factorization.

256507724562121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14112000, while the sum is 55.

The spelling of 256507724562121 in words is "two hundred fifty-six trillion, five hundred seven billion, seven hundred twenty-four million, five hundred sixty-two thousand, one hundred twenty-one".