261405222 has 64 divisors (see below), whose sum is σ = 589498560. Its totient is φ = 76737024.

The previous prime is 261405187. The next prime is 261405239. The reversal of 261405222 is 222504162.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 261405192 and 261405201.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 152104 + ... + 153812.

It is an arithmetic number, because the mean of its divisors is an integer number (9210915).

Almost surely, 2^261405222 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261405222, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (294749280).

261405222 is an abundant number, since it is smaller than the sum of its proper divisors (328093338).

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

261405222 is a wasteful number, since it uses less digits than its factorization.

261405222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1817.

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 261405222 is about 16168.0308634045. The cubic root of 261405222 is about 639.3982152505.

Adding to 261405222 its reverse (222504162), we get a palindrome (483909384).

The spelling of 261405222 in words is "two hundred sixty-one million, four hundred five thousand, two hundred twenty-two".