261031680 has 576 divisors, whose sum is σ = 1153797120. Its totient is φ = 54411264.

The previous prime is 261031657. The next prime is 261031691. The reversal of 261031680 is 86130162.

It is a tau number, because it is divible by the number of its divisors (576).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a zygodrome in base 2.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3144919 + ... + 3145001.

It is an arithmetic number, because the mean of its divisors is an integer number (2003120).

Almost surely, 2^261031680 is an apocalyptic number.

261031680 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 261031680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (576898560).

261031680 is an abundant number, since it is smaller than the sum of its proper divisors (892765440).

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

261031680 is a wasteful number, since it uses less digits than its factorization.

261031680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133 (or 113 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 261031680 is about 16156.4748630387. The cubic root of 261031680 is about 639.0935083242.

The spelling of 261031680 in words is "two hundred sixty-one million, thirty-one thousand, six hundred eighty".