261436129 has 4 divisors (see below), whose sum is σ = 265118400. Its totient is φ = 257753860.

The previous prime is 261436111. The next prime is 261436151. The reversal of 261436129 is 921634162.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 261436129 - 2²⁵ = 227881697 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 261436094 and 261436103.

It is not an unprimeable number, because it can be changed into a prime (261436169) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1841029 + ... + 1841170.

It is an arithmetic number, because the mean of its divisors is an integer number (66279600).

Almost surely, 2^261436129 is an apocalyptic number.

It is an amenable number.

261436129 is a deficient number, since it is larger than the sum of its proper divisors (3682271).

261436129 is an equidigital number, since it uses as much as digits as its factorization.

261436129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3682270.

The product of its digits is 15552, while the sum is 34.

The square root of 261436129 is about 16168.9866410978. The cubic root of 261436129 is about 639.4234138058.

The spelling of 261436129 in words is "two hundred sixty-one million, four hundred thirty-six thousand, one hundred twenty-nine".