261009913 has 2 divisors, whose sum is σ = 261009914. Its totient is φ = 261009912.

The previous prime is 261009907. The next prime is 261009937. The reversal of 261009913 is 319900162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 258662889 + 2347024 = 16083^2 + 1532^2 .

It is a cyclic number.

It is not a de Polignac number, because 261009913 - 2⁹ = 261009401 is a prime.

It is not a weakly prime, because it can be changed into another prime (261009943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130504956 + 130504957.

It is an arithmetic number, because the mean of its divisors is an integer number (130504957).

Almost surely, 2^261009913 is an apocalyptic number.

It is an amenable number.

261009913 is a deficient number, since it is larger than the sum of its proper divisors (1).

261009913 is an equidigital number, since it uses as much as digits as its factorization.

261009913 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2916, while the sum is 31.

The square root of 261009913 is about 16155.8012181383. The cubic root of 261009913 is about 639.0757435135.

The spelling of 261009913 in words is "two hundred sixty-one million, nine thousand, nine hundred thirteen".