261761920 has 192 divisors, whose sum is σ = 772331760. Its totient is φ = 84295680.

The previous prime is 261761887. The next prime is 261761921. The reversal of 261761920 is 29167162.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261761921) 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, 532875 + ... + 533365.

Almost surely, 2^261761920 is an apocalyptic number.

261761920 is a gapful number since it is divisible by the number (20) 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 261761920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (386165880).

261761920 is an abundant number, since it is smaller than the sum of its proper divisors (510569840).

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

261761920 is a wasteful number, since it uses less digits than its factorization.

261761920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 541 (or 522 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 261761920 is about 16179.0580689977. The cubic root of 261761920 is about 639.6889113117.

The spelling of 261761920 in words is "two hundred sixty-one million, seven hundred sixty-one thousand, nine hundred twenty".