261945061 has 16 divisors (see below), whose sum is σ = 318404736. Its totient is φ = 210364416.

The previous prime is 261945043. The next prime is 261945113. The reversal of 261945061 is 160549162.

It is a cyclic number.

It is not a de Polignac number, because 261945061 - 2²⁷ = 127727333 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261945031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22165 + ... + 31861.

It is an arithmetic number, because the mean of its divisors is an integer number (19900296).

Almost surely, 2^261945061 is an apocalyptic number.

It is an amenable number.

261945061 is a deficient number, since it is larger than the sum of its proper divisors (56459675).

261945061 is a wasteful number, since it uses less digits than its factorization.

261945061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9948.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 261945061 is about 16184.7168958867. The cubic root of 261945061 is about 639.8380620560.

The spelling of 261945061 in words is "two hundred sixty-one million, nine hundred forty-five thousand, sixty-one".