261410640 has 240 divisors, whose sum is σ = 888693120. Its totient is φ = 63472640.

The previous prime is 261410627. The next prime is 261410641. The reversal of 261410640 is 46014162.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 261410640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261410641) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3681805 + ... + 3681875.

It is an arithmetic number, because the mean of its divisors is an integer number (3702888).

Almost surely, 2^261410640 is an apocalyptic number.

261410640 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 261410640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (444346560).

261410640 is an abundant number, since it is smaller than the sum of its proper divisors (627282480).

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

261410640 is a wasteful number, since it uses less digits than its factorization.

261410640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162 (or 133 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 261410640 is about 16168.1984154079. The cubic root of 261410640 is about 639.4026327031.

The spelling of 261410640 in words is "two hundred sixty-one million, four hundred ten thousand, six hundred forty".