261123220 has 12 divisors (see below), whose sum is σ = 548358804. Its totient is φ = 104449280.

The previous prime is 261123197. The next prime is 261123227. The reversal of 261123220 is 22321162.

It can be written as a sum of positive squares in 2 ways, for example, as 57547396 + 203575824 = 7586^2 + 14268^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261123227) by changing a digit.

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, 6528061 + ... + 6528100.

It is an arithmetic number, because the mean of its divisors is an integer number (45696567).

Almost surely, 2^261123220 is an apocalyptic number.

261123220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261123220 is an abundant number, since it is smaller than the sum of its proper divisors (287235584).

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

261123220 is a wasteful number, since it uses less digits than its factorization.

261123220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13056170 (or 13056168 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 261123220 is about 16159.3075346687. The cubic root of 261123220 is about 639.1682065146.

Adding to 261123220 its reverse (22321162), we get a palindrome (283444382).

The spelling of 261123220 in words is "two hundred sixty-one million, one hundred twenty-three thousand, two hundred twenty".