261444163 has 4 divisors (see below), whose sum is σ = 265875480. Its totient is φ = 257012848.

The previous prime is 261444149. The next prime is 261444181. The reversal of 261444163 is 361444162.

261444163 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 361444162 = 2 ⋅180722081.

It is a cyclic number.

It is not a de Polignac number, because 261444163 - 2¹³ = 261435971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261444143) 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, 2215570 + ... + 2215687.

It is an arithmetic number, because the mean of its divisors is an integer number (66468870).

Almost surely, 2^261444163 is an apocalyptic number.

261444163 is a deficient number, since it is larger than the sum of its proper divisors (4431317).

261444163 is an equidigital number, since it uses as much as digits as its factorization.

261444163 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4431316.

The product of its digits is 13824, while the sum is 31.

The square root of 261444163 is about 16169.2350777642. The cubic root of 261444163 is about 639.4299636211.

Subtracting 261444163 from its reverse (361444162), we obtain a palindrome (99999999).

The spelling of 261444163 in words is "two hundred sixty-one million, four hundred forty-four thousand, one hundred sixty-three".