261633424 has 20 divisors (see below), whose sum is σ = 545908636. Its totient is φ = 120753792.

The previous prime is 261633413. The next prime is 261633433. The reversal of 261633424 is 424336162.

It can be written as a sum of positive squares in 2 ways, for example, as 14137600 + 247495824 = 3760^2 + 15732^2 .

It is a super-4 number, since 4×261633424⁴ (a number of 35 digits) contains 4444 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 628719 + ... + 629134.

Almost surely, 2^261633424 is an apocalyptic number.

It is an amenable number.

261633424 is an abundant number, since it is smaller than the sum of its proper divisors (284275212).

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

261633424 is a wasteful number, since it uses less digits than its factorization.

261633424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1257874 (or 1257868 counting only the distinct ones).

The product of its digits is 20736, while the sum is 31.

The square root of 261633424 is about 16175.0865221797. The cubic root of 261633424 is about 639.5842221347.

Adding to 261633424 its reverse (424336162), we get a palindrome (685969586).

The spelling of 261633424 in words is "two hundred sixty-one million, six hundred thirty-three thousand, four hundred twenty-four".