261422605 has 4 divisors (see below), whose sum is σ = 313707132. Its totient is φ = 209138080.

The previous prime is 261422599. The next prime is 261422611. The reversal of 261422605 is 506224162.

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

It is an interprime number because it is at equal distance from previous prime (261422599) and next prime (261422611).

It can be written as a sum of positive squares in 2 ways, for example, as 168454441 + 92968164 = 12979^2 + 9642^2 .

It is not a de Polignac number, because 261422605 - 2⁵ = 261422573 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 26142256 + ... + 26142265.

It is an arithmetic number, because the mean of its divisors is an integer number (78426783).

Almost surely, 2^261422605 is an apocalyptic number.

It is an amenable number.

261422605 is a deficient number, since it is larger than the sum of its proper divisors (52284527).

261422605 is an equidigital number, since it uses as much as digits as its factorization.

261422605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52284526.

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 261422605 is about 16168.5684276624. The cubic root of 261422605 is about 639.4123878987.

Adding to 261422605 its reverse (506224162), we get a palindrome (767646767).

The spelling of 261422605 in words is "two hundred sixty-one million, four hundred twenty-two thousand, six hundred five".