261865828 has 48 divisors (see below), whose sum is σ = 553598080. Its totient is φ = 105878016.

The previous prime is 261865823. The next prime is 261865837. The reversal of 261865828 is 828568162.

It is not an unprimeable number, because it can be changed into a prime (261865823) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 146476 + ... + 148252.

Almost surely, 2^261865828 is an apocalyptic number.

261865828 is a gapful number since it is divisible by the number (28) 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 261865828, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (276799040).

261865828 is an abundant number, since it is smaller than the sum of its proper divisors (291732252).

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

261865828 is a wasteful number, since it uses less digits than its factorization.

261865828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2084 (or 2082 counting only the distinct ones).

The product of its digits is 368640, while the sum is 46.

The square root of 261865828 is about 16182.2689385636. The cubic root of 261865828 is about 639.7735429269.

The spelling of 261865828 in words is "two hundred sixty-one million, eight hundred sixty-five thousand, eight hundred twenty-eight".