261188928 has 448 divisors, whose sum is σ = 1037783040. Its totient is φ = 62208000.

The previous prime is 261188909. The next prime is 261188947. The reversal of 261188928 is 829881162.

It is a happy number.

261188928 is a `hidden beast` number, since 2 + 611 + 8 + 8 + 9 + 28 = 666.

It is an interprime number because it is at equal distance from previous prime (261188909) and next prime (261188947).

It is a tau number, because it is divible by the number of its divisors (448).

It is a super-2 number, since 2×261188928² = 136439312219578368, 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 an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 1729653 + ... + 1729803.

It is an arithmetic number, because the mean of its divisors is an integer number (2316480).

Almost surely, 2^261188928 is an apocalyptic number.

261188928 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 261188928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (518891520).

261188928 is an abundant number, since it is smaller than the sum of its proper divisors (776594112).

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

261188928 is a wasteful number, since it uses less digits than its factorization.

261188928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203 (or 187 counting only the distinct ones).

The product of its digits is 110592, while the sum is 45.

The square root of 261188928 is about 16161.3405384578. The cubic root of 261188928 is about 639.2218145931.

The spelling of 261188928 in words is "two hundred sixty-one million, one hundred eighty-eight thousand, nine hundred twenty-eight".