261813042 has 48 divisors (see below), whose sum is σ = 592720128. Its totient is φ = 83423520.

The previous prime is 261813023. The next prime is 261813047. The reversal of 261813042 is 240318162.

261813042 is a `hidden beast` number, since 2 + 618 + 1 + 3 + 0 + 42 = 666.

It is a super-2 number, since 2×261813042² = 137092137922587528, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 261812997 and 261813015.

It is not an unprimeable number, because it can be changed into a prime (261813047) 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 23 ways as a sum of consecutive naturals, for example, 43488 + ... + 49140.

It is an arithmetic number, because the mean of its divisors is an integer number (12348336).

Almost surely, 2^261813042 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261813042, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (296360064).

261813042 is an abundant number, since it is smaller than the sum of its proper divisors (330907086).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261813042 is a wasteful number, since it uses less digits than its factorization.

261813042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5775 (or 5772 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 261813042 is about 16180.6378737057. The cubic root of 261813042 is about 639.7305522653.

The spelling of 261813042 in words is "two hundred sixty-one million, eight hundred thirteen thousand, forty-two".