261155729 has 2 divisors, whose sum is σ = 261155730. Its totient is φ = 261155728.

The previous prime is 261155677. The next prime is 261155737. The reversal of 261155729 is 927551162.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 238640704 + 22515025 = 15448^2 + 4745^2 .

It is a cyclic number.

It is not a de Polignac number, because 261155729 - 2⁸ = 261155473 is a prime.

It is equal to p_14255597 and since 261155729 and 14255597 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 261155692 and 261155701.

It is not a weakly prime, because it can be changed into another prime (261155789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130577864 + 130577865.

It is an arithmetic number, because the mean of its divisors is an integer number (130577865).

Almost surely, 2^261155729 is an apocalyptic number.

It is an amenable number.

261155729 is a deficient number, since it is larger than the sum of its proper divisors (1).

261155729 is an equidigital number, since it uses as much as digits as its factorization.

261155729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 37800, while the sum is 38.

The square root of 261155729 is about 16160.3133942384. The cubic root of 261155729 is about 639.1947302084.

The spelling of 261155729 in words is "two hundred sixty-one million, one hundred fifty-five thousand, seven hundred twenty-nine".