261215040 has 112 divisors (see below), whose sum is σ = 873069120. Its totient is φ = 65986560.

The previous prime is 261215039. The next prime is 261215063. The reversal of 261215040 is 40512162.

It is a junction number, because it is equal to n+sod(n) for n = 261214998 and 261215016.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 11080 + ... + 25400.

It is an arithmetic number, because the mean of its divisors is an integer number (7795260).

Almost surely, 2^261215040 is an apocalyptic number.

261215040 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 261215040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (436534560).

261215040 is an abundant number, since it is smaller than the sum of its proper divisors (611854080).

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

261215040 is a wasteful number, since it uses less digits than its factorization.

261215040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14360 (or 14350 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 261215040 is about 16162.1483720451. The cubic root of 261215040 is about 639.2431156540.

The spelling of 261215040 in words is "two hundred sixty-one million, two hundred fifteen thousand, forty".