261222828 has 12 divisors (see below), whose sum is σ = 609519960. Its totient is φ = 87074272.

The previous prime is 261222827. The next prime is 261222877. The reversal of 261222828 is 828222162.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (261222823) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10884273 + ... + 10884296.

It is an arithmetic number, because the mean of its divisors is an integer number (50793330).

Almost surely, 2^261222828 is an apocalyptic number.

It is an amenable number.

261222828 is an abundant number, since it is smaller than the sum of its proper divisors (348297132).

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

261222828 is a wasteful number, since it uses less digits than its factorization.

261222828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21768576 (or 21768574 counting only the distinct ones).

The product of its digits is 12288, while the sum is 33.

The square root of 261222828 is about 16162.3893035652. The cubic root of 261222828 is about 639.2494684989.

The spelling of 261222828 in words is "two hundred sixty-one million, two hundred twenty-two thousand, eight hundred twenty-eight".