261283909 has 4 divisors (see below), whose sum is σ = 261955980. Its totient is φ = 260611840.

The previous prime is 261283879. The next prime is 261283927. The reversal of 261283909 is 909382162.

It is a happy number.

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 17455684 + 243828225 = 4178^2 + 15615^2 .

It is a cyclic number.

It is not a de Polignac number, because 261283909 - 2⁹ = 261283397 is a prime.

It is a super-2 number, since 2×261283909² = 136538562204640562, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261280909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 335452 + ... + 336229.

It is an arithmetic number, because the mean of its divisors is an integer number (65488995).

Almost surely, 2^261283909 is an apocalyptic number.

It is an amenable number.

261283909 is a deficient number, since it is larger than the sum of its proper divisors (672071).

261283909 is an equidigital number, since it uses as much as digits as its factorization.

261283909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 672070.

The product of its (nonzero) digits is 46656, while the sum is 40.

The square root of 261283909 is about 16164.2787961604. The cubic root of 261283909 is about 639.2992892518.

The spelling of 261283909 in words is "two hundred sixty-one million, two hundred eighty-three thousand, nine hundred nine".