261389107 has 4 divisors (see below), whose sum is σ = 298730416. Its totient is φ = 224047800.

The previous prime is 261389069. The next prime is 261389113. The reversal of 261389107 is 701983162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 701983162 = 2 ⋅350991581.

It is a cyclic number.

It is not a de Polignac number, because 261389107 - 2¹⁹ = 260864819 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261389197) by changing a digit.

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, 18670644 + ... + 18670657.

It is an arithmetic number, because the mean of its divisors is an integer number (74682604).

Almost surely, 2^261389107 is an apocalyptic number.

261389107 is a deficient number, since it is larger than the sum of its proper divisors (37341309).

261389107 is an equidigital number, since it uses as much as digits as its factorization.

261389107 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37341308.

The product of its (nonzero) digits is 18144, while the sum is 37.

The square root of 261389107 is about 16167.5324957150. The cubic root of 261389107 is about 639.3850758624.

It can be divided in two parts, 26138 and 9107, that added together give a triangular number (35245 = T₂₆₅).

The spelling of 261389107 in words is "two hundred sixty-one million, three hundred eighty-nine thousand, one hundred seven".