261222120 has 192 divisors, whose sum is σ = 889574400. Its totient is φ = 66401280.

The previous prime is 261222083. The next prime is 261222131. The reversal of 261222120 is 21222162.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 261222093 and 261222102.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 993109 + ... + 993371.

It is an arithmetic number, because the mean of its divisors is an integer number (4633200).

Almost surely, 2^261222120 is an apocalyptic number.

261222120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261222120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (444787200).

261222120 is an abundant number, since it is smaller than the sum of its proper divisors (628352280).

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

261222120 is a wasteful number, since it uses less digits than its factorization.

261222120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 400 (or 393 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 261222120 is about 16162.3674008482. The cubic root of 261222120 is about 639.2488909728.

Adding to 261222120 its reverse (21222162), we get a palindrome (282444282).

The spelling of 261222120 in words is "two hundred sixty-one million, two hundred twenty-two thousand, one hundred twenty".