261404928 has 144 divisors (see below), whose sum is σ = 787348800. Its totient is φ = 85524480.

The previous prime is 261404921. The next prime is 261404939. The reversal of 261404928 is 829404162.

261404928 is a `hidden beast` number, since 26 + 140 + 492 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 261404892 and 261404901.

It is not an unprimeable number, because it can be changed into a prime (261404921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 407488 + ... + 408128.

It is an arithmetic number, because the mean of its divisors is an integer number (5467700).

Almost surely, 2^261404928 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261404928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (393674400).

261404928 is an abundant number, since it is smaller than the sum of its proper divisors (525943872).

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

261404928 is an equidigital number, since it uses as much as digits as its factorization.

261404928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 725 (or 705 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 261404928 is about 16168.0217713856. The cubic root of 261404928 is about 639.3979755420.

The spelling of 261404928 in words is "two hundred sixty-one million, four hundred four thousand, nine hundred twenty-eight".