261536236651553 has 2 divisors, whose sum is σ = 261536236651554. Its totient is φ = 261536236651552.

The previous prime is 261536236651463. The next prime is 261536236651559. The reversal of 261536236651553 is 355156632635162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 225287251623184 + 36248985028369 = 15009572^2 + 6020713^2 .

It is a cyclic number.

It is not a de Polignac number, because 261536236651553 - 2¹² = 261536236647457 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 261536236651492 and 261536236651501.

It is not a weakly prime, because it can be changed into another prime (261536236651559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130768118325776 + 130768118325777.

It is an arithmetic number, because the mean of its divisors is an integer number (130768118325777).

Almost surely, 2^{261536236651553} is an apocalyptic number.

It is an amenable number.

261536236651553 is a deficient number, since it is larger than the sum of its proper divisors (1).

261536236651553 is an equidigital number, since it uses as much as digits as its factorization.

261536236651553 is an evil number, because the sum of its binary digits is even.

The product of its digits is 87480000, while the sum is 59.

The spelling of 261536236651553 in words is "two hundred sixty-one trillion, five hundred thirty-six billion, two hundred thirty-six million, six hundred fifty-one thousand, five hundred fifty-three".