261899568 has 120 divisors (see below), whose sum is σ = 868777728. Its totient is φ = 74820672.

The previous prime is 261899567. The next prime is 261899621. The reversal of 261899568 is 865998162.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (261899567) 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 23 ways as a sum of consecutive naturals, for example, 22405 + ... + 32027.

Almost surely, 2^261899568 is an apocalyptic number.

261899568 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 261899568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (434388864).

261899568 is an abundant number, since it is smaller than the sum of its proper divisors (606878160).

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

261899568 is an equidigital number, since it uses as much as digits as its factorization.

261899568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9653 (or 9635 counting only the distinct ones).

The product of its digits is 1866240, while the sum is 54.

The square root of 261899568 is about 16183.3114040359. The cubic root of 261899568 is about 639.8010188708.

The spelling of 261899568 in words is "two hundred sixty-one million, eight hundred ninety-nine thousand, five hundred sixty-eight".