261633421 has 16 divisors (see below), whose sum is σ = 303379200. Its totient is φ = 221005440.

The previous prime is 261633413. The next prime is 261633433. The reversal of 261633421 is 124336162.

It is a cyclic number.

It is not a de Polignac number, because 261633421 - 2³ = 261633413 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261633421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261633721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 141976 + ... + 143806.

It is an arithmetic number, because the mean of its divisors is an integer number (18961200).

Almost surely, 2^261633421 is an apocalyptic number.

It is an amenable number.

261633421 is a deficient number, since it is larger than the sum of its proper divisors (41745779).

261633421 is a wasteful number, since it uses less digits than its factorization.

261633421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2124.

The product of its digits is 5184, while the sum is 28.

The square root of 261633421 is about 16175.0864294445. The cubic root of 261633421 is about 639.5842196901.

Adding to 261633421 its reverse (124336162), we get a palindrome (385969583).

It can be divided in two parts, 26163 and 3421, that added together give a square (29584 = 172²).

The spelling of 261633421 in words is "two hundred sixty-one million, six hundred thirty-three thousand, four hundred twenty-one".