261889488 has 360 divisors, whose sum is σ = 950177280. Its totient is φ = 65802240.

The previous prime is 261889487. The next prime is 261889493. The reversal of 261889488 is 884988162.

It is a Cunningham number, because it is equal to 16183²-1.

It is a super-2 number, since 2×261889488² = 137172207849804288, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261889487) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 8448033 + ... + 8448063.

Almost surely, 2^261889488 is an apocalyptic number.

261889488 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 261889488, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (475088640).

261889488 is an abundant number, since it is smaller than the sum of its proper divisors (688287792).

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

261889488 is a wasteful number, since it uses less digits than its factorization.

261889488 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115 (or 89 counting only the distinct ones).

The product of its digits is 1769472, while the sum is 54.

The square root of 261889488 is about 16182.9999691034. Note that the first 4 decimals coincide. The cubic root of 261889488 is about 639.7928105372.

The spelling of 261889488 in words is "two hundred sixty-one million, eight hundred eighty-nine thousand, four hundred eighty-eight".