261323613 has 6 divisors (see below), whose sum is σ = 377467454. Its totient is φ = 174215736.

The previous prime is 261323603. The next prime is 261323633. The reversal of 261323613 is 316323162.

It is a happy number.

261323613 is a `hidden beast` number, since 2 + 613 + 2 + 36 + 13 = 666.

It can be written as a sum of positive squares in only one way, i.e., 156425049 + 104898564 = 12507^2 + 10242^2 .

It is not a de Polignac number, because 261323613 - 2¹² = 261319517 is a prime.

It is a super-2 number, since 2×261323613² = 136580061422747538, 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 (261323603) 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 5 ways as a sum of consecutive naturals, for example, 14517970 + ... + 14517987.

Almost surely, 2^261323613 is an apocalyptic number.

It is an amenable number.

261323613 is a deficient number, since it is larger than the sum of its proper divisors (116143841).

261323613 is a wasteful number, since it uses less digits than its factorization.

261323613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29035963 (or 29035960 counting only the distinct ones).

The product of its digits is 3888, while the sum is 27.

The square root of 261323613 is about 16165.5068896710. The cubic root of 261323613 is about 639.3316696785.

Adding to 261323613 its reverse (316323162), we get a palindrome (577646775).

The spelling of 261323613 in words is "two hundred sixty-one million, three hundred twenty-three thousand, six hundred thirteen".