261537268320 has 576 divisors, whose sum is σ = 928215288000. Its totient is φ = 67025387520.

The previous prime is 261537268319. The next prime is 261537268327. The reversal of 261537268320 is 23862735162.

261537268320 is a `hidden beast` number, since 2 + 61 + 5 + 3 + 7 + 268 + 320 = 666.

261537268320 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261537268327) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1239513015 + ... + 1239513225.

It is an arithmetic number, because the mean of its divisors is an integer number (1611484875).

Almost surely, 2^261537268320 is an apocalyptic number.

261537268320 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 261537268320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (464107644000).

261537268320 is an abundant number, since it is smaller than the sum of its proper divisors (666678019680).

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

261537268320 is a wasteful number, since it uses less digits than its factorization.

261537268320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 543 (or 532 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 45.

The spelling of 261537268320 in words is "two hundred sixty-one billion, five hundred thirty-seven million, two hundred sixty-eight thousand, three hundred twenty".