261444220 has 48 divisors (see below), whose sum is σ = 588426048. Its totient is φ = 97320960.

The previous prime is 261444187. The next prime is 261444247. The reversal of 261444220 is 22444162.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9340 + ... + 24700.

It is an arithmetic number, because the mean of its divisors is an integer number (12258876).

Almost surely, 2^261444220 is an apocalyptic number.

261444220 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 261444220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (294213024).

261444220 is an abundant number, since it is smaller than the sum of its proper divisors (326981828).

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

261444220 is a wasteful number, since it uses less digits than its factorization.

261444220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15430 (or 15428 counting only the distinct ones).

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

The square root of 261444220 is about 16169.2368403707. The cubic root of 261444220 is about 639.4300100906.

Adding to 261444220 its reverse (22444162), we get a palindrome (283888382).

The spelling of 261444220 in words is "two hundred sixty-one million, four hundred forty-four thousand, two hundred twenty".