261981153757 has 2 divisors, whose sum is σ = 261981153758. Its totient is φ = 261981153756.

The previous prime is 261981153739. The next prime is 261981153803. The reversal of 261981153757 is 757351189162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 172568791396 + 89412362361 = 415414^2 + 299019^2 .

It is a cyclic number.

It is not a de Polignac number, because 261981153757 - 2³⁵ = 227621415389 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 261981153698 and 261981153707.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261981150757) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130990576878 + 130990576879.

It is an arithmetic number, because the mean of its divisors is an integer number (130990576879).

Almost surely, 2^261981153757 is an apocalyptic number.

It is an amenable number.

261981153757 is a deficient number, since it is larger than the sum of its proper divisors (1).

261981153757 is an equidigital number, since it uses as much as digits as its factorization.

261981153757 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3175200, while the sum is 55.

The spelling of 261981153757 in words is "two hundred sixty-one billion, nine hundred eighty-one million, one hundred fifty-three thousand, seven hundred fifty-seven".