261252635401 has 2 divisors, whose sum is σ = 261252635402. Its totient is φ = 261252635400.

The previous prime is 261252635389. The next prime is 261252635419. The reversal of 261252635401 is 104536252162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 207593229376 + 53659406025 = 455624^2 + 231645^2 .

It is a cyclic number.

It is not a de Polignac number, because 261252635401 - 2¹⁷ = 261252504329 is a prime.

It is not a weakly prime, because it can be changed into another prime (261252635491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130626317700 + 130626317701.

It is an arithmetic number, because the mean of its divisors is an integer number (130626317701).

Almost surely, 2^261252635401 is an apocalyptic number.

It is an amenable number.

261252635401 is a deficient number, since it is larger than the sum of its proper divisors (1).

261252635401 is an equidigital number, since it uses as much as digits as its factorization.

261252635401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 86400, while the sum is 37.

Adding to 261252635401 its reverse (104536252162), we get a palindrome (365788887563).

The spelling of 261252635401 in words is "two hundred sixty-one billion, two hundred fifty-two million, six hundred thirty-five thousand, four hundred one".