261811602 has 112 divisors (see below), whose sum is σ = 668391360. Its totient is φ = 76212576.

The previous prime is 261811601. The next prime is 261811619. The reversal of 261811602 is 206118162.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (261811601) 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 55 ways as a sum of consecutive naturals, for example, 359763 + ... + 360489.

It is an arithmetic number, because the mean of its divisors is an integer number (5967780).

Almost surely, 2^261811602 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261811602, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (334195680).

261811602 is an abundant number, since it is smaller than the sum of its proper divisors (406579758).

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

261811602 is a wasteful number, since it uses less digits than its factorization.

261811602 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 779 (or 764 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 261811602 is about 16180.5933760168. The cubic root of 261811602 is about 639.7293794008.

Adding to 261811602 its reverse (206118162), we get a palindrome (467929764).

The spelling of 261811602 in words is "two hundred sixty-one million, eight hundred eleven thousand, six hundred two".