261404224 has 63 divisors (see below), whose sum is σ = 542607627. Its totient is φ = 124946304.

The previous prime is 261404197. The next prime is 261404239. The reversal of 261404224 is 422404162.

It is a happy number.

The square root of 261404224 is 16168.

It is a perfect power (a square), and thus also a powerful number.

It is a Duffinian number.

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 8 ways as a sum of consecutive naturals, for example, 5561769 + ... + 5561815.

Almost surely, 2^261404224 is an apocalyptic number.

261404224 is the 16168-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261404224

261404224 is an abundant number, since it is smaller than the sum of its proper divisors (281203403).

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

261404224 is an frugal number, since it uses more digits than its factorization.

261404224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192 (or 92 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 25.

The cubic root of 261404224 is about 639.3974015454.

Multiplying 261404224 by its sum of digits (25), we get a square (6535105600 = 80840²).

Adding to 261404224 its reverse (422404162), we get a palindrome (683808386).

The spelling of 261404224 in words is "two hundred sixty-one million, four hundred four thousand, two hundred twenty-four".