261805520653 has 2 divisors, whose sum is σ = 261805520654. Its totient is φ = 261805520652.

The previous prime is 261805520593. The next prime is 261805520663. The reversal of 261805520653 is 356025508162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 232688534884 + 29116985769 = 482378^2 + 170637^2 .

It is a cyclic number.

It is not a de Polignac number, because 261805520653 - 2¹³ = 261805512461 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261805520663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130902760326 + 130902760327.

It is an arithmetic number, because the mean of its divisors is an integer number (130902760327).

Almost surely, 2^261805520653 is an apocalyptic number.

It is an amenable number.

261805520653 is a deficient number, since it is larger than the sum of its proper divisors (1).

261805520653 is an equidigital number, since it uses as much as digits as its factorization.

261805520653 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432000, while the sum is 43.

The spelling of 261805520653 in words is "two hundred sixty-one billion, eight hundred five million, five hundred twenty thousand, six hundred fifty-three".