261543377 has 2 divisors, whose sum is σ = 261543378. Its totient is φ = 261543376.

The previous prime is 261543353. The next prime is 261543389. The reversal of 261543377 is 773345162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 259983376 + 1560001 = 16124^2 + 1249^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261543377 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261543377.

It is not a weakly prime, because it can be changed into another prime (261543397) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130771688 + 130771689.

It is an arithmetic number, because the mean of its divisors is an integer number (130771689).

Almost surely, 2^261543377 is an apocalyptic number.

It is an amenable number.

261543377 is a deficient number, since it is larger than the sum of its proper divisors (1).

261543377 is an equidigital number, since it uses as much as digits as its factorization.

261543377 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 105840, while the sum is 38.

The square root of 261543377 is about 16172.3027735694. The cubic root of 261543377 is about 639.5108379724.

The spelling of 261543377 in words is "two hundred sixty-one million, five hundred forty-three thousand, three hundred seventy-seven".