261521094240 has 288 divisors, whose sum is σ = 1023224057856. Its totient is φ = 59583329280.

The previous prime is 261521094187. The next prime is 261521094251. The reversal of 261521094240 is 42490125162.

It is a happy number.

261521094240 is a `hidden beast` number, since 2 + 6 + 1 + 521 + 0 + 94 + 2 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a super-2 number, since 2×261521094240² (a number of 24 digits) contains 22 as substring.

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 = 261521094195 and 261521094204.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3093169 + ... + 3176591.

It is an arithmetic number, because the mean of its divisors is an integer number (3552861312).

Almost surely, 2^261521094240 is an apocalyptic number.

261521094240 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 261521094240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (511612028928).

261521094240 is an abundant number, since it is smaller than the sum of its proper divisors (761702963616).

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

261521094240 is a wasteful number, since it uses less digits than its factorization.

261521094240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83762 (or 83751 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The spelling of 261521094240 in words is "two hundred sixty-one billion, five hundred twenty-one million, ninety-four thousand, two hundred forty".