261621360 has 640 divisors, whose sum is σ = 1219921920. Its totient is φ = 50181120.

The previous prime is 261621341. The next prime is 261621401. The reversal of 261621360 is 63126162.

261621360 is a `hidden beast` number, since 2 + 6 + 1 + 621 + 36 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a zygodrome in base 2.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 20124714 + ... + 20124726.

It is an arithmetic number, because the mean of its divisors is an integer number (1906128).

Almost surely, 2^261621360 is an apocalyptic number.

261621360 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 261621360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (609960960).

261621360 is an abundant number, since it is smaller than the sum of its proper divisors (958300560).

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

261621360 is a wasteful number, since it uses less digits than its factorization.

261621360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75 (or 41 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 261621360 is about 16174.7135987009. The cubic root of 261621360 is about 639.5743915066.

The spelling of 261621360 in words is "two hundred sixty-one million, six hundred twenty-one thousand, three hundred sixty".