261061081 has 4 divisors (see below), whose sum is σ = 262144564. Its totient is φ = 259977600.

The previous prime is 261061079. The next prime is 261061091. The reversal of 261061081 is 180160162.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 137851081 + 123210000 = 11741^2 + 11100^2 .

It is a cyclic number.

It is not a de Polignac number, because 261061081 - 2¹ = 261061079 is a prime.

It is a super-2 number, since 2×261061081² = 136305776025777122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261061001) 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 3 ways as a sum of consecutive naturals, for example, 541380 + ... + 541861.

It is an arithmetic number, because the mean of its divisors is an integer number (65536141).

Almost surely, 2^261061081 is an apocalyptic number.

It is an amenable number.

261061081 is a deficient number, since it is larger than the sum of its proper divisors (1083483).

261061081 is a wasteful number, since it uses less digits than its factorization.

261061081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1083482.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 261061081 is about 16157.3847203067. The cubic root of 261061081 is about 639.1175019416.

The spelling of 261061081 in words is "two hundred sixty-one million, sixty-one thousand, eighty-one".