261784770 has 128 divisors (see below), whose sum is σ = 712212480. Its totient is φ = 61136640.

The previous prime is 261784753. The next prime is 261784771. The reversal of 261784770 is 77487162.

It is not an unprimeable number, because it can be changed into a prime (261784771) 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 63 ways as a sum of consecutive naturals, for example, 713127 + ... + 713493.

It is an arithmetic number, because the mean of its divisors is an integer number (5564160).

Almost surely, 2^261784770 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261784770, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (356106240).

261784770 is an abundant number, since it is smaller than the sum of its proper divisors (450427710).

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

261784770 is a wasteful number, since it uses less digits than its factorization.

261784770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 480.

The product of its (nonzero) digits is 131712, while the sum is 42.

The square root of 261784770 is about 16179.7642133623. The cubic root of 261784770 is about 639.7075242385.

The spelling of 261784770 in words is "two hundred sixty-one million, seven hundred eighty-four thousand, seven hundred seventy".