261615456 has 72 divisors (see below), whose sum is σ = 764107344. Its totient is φ = 84844800.

The previous prime is 261615451. The next prime is 261615491. The reversal of 261615456 is 654516162.

It is a tau number, because it is divible by the number of its divisors (72).

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

It is a self number, because there is not a number n which added to its sum of digits gives 261615456.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261615451) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1620 + ... + 22931.

It is an arithmetic number, because the mean of its divisors is an integer number (10612602).

Almost surely, 2^261615456 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 261615456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (382053672).

261615456 is an abundant number, since it is smaller than the sum of its proper divisors (502491888).

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

261615456 is a wasteful number, since it uses less digits than its factorization.

261615456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24604 (or 24593 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 261615456 is about 16174.5310905757. The cubic root of 261615456 is about 639.5695803862.

The spelling of 261615456 in words is "two hundred sixty-one million, six hundred fifteen thousand, four hundred fifty-six".