261261220 has 24 divisors (see below), whose sum is σ = 598526208. Its totient is φ = 95004000.

The previous prime is 261261197. The next prime is 261261223. The reversal of 261261220 is 22162162.

261261220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a junction number, because it is equal to n+sod(n) for n = 261261191 and 261261200.

It is not an unprimeable number, because it can be changed into a prime (261261223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 593556 + ... + 593995.

It is an arithmetic number, because the mean of its divisors is an integer number (24938592).

Almost surely, 2^261261220 is an apocalyptic number.

261261220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261261220 is an abundant number, since it is smaller than the sum of its proper divisors (337264988).

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

261261220 is a wasteful number, since it uses less digits than its factorization.

261261220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1187571 (or 1187569 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 261261220 is about 16163.5769556123. The cubic root of 261261220 is about 639.2807838624.

The spelling of 261261220 in words is "two hundred sixty-one million, two hundred sixty-one thousand, two hundred twenty".