21611260440 has 768 divisors, whose sum is σ = 94753152000. Its totient is φ = 4135587840.

The previous prime is 21611260409. The next prime is 21611260469. The reversal of 21611260440 is 4406211612.

21611260440 is a `hidden beast` number, since 2 + 1 + 6 + 1 + 12 + 604 + 40 = 666.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 19486606 + ... + 19487714.

It is an arithmetic number, because the mean of its divisors is an integer number (123376500).

Almost surely, 2^21611260440 is an apocalyptic number.

21611260440 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 21611260440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47376576000).

21611260440 is an abundant number, since it is smaller than the sum of its proper divisors (73141891560).

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

21611260440 is a wasteful number, since it uses less digits than its factorization.

21611260440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1200 (or 1193 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The spelling of 21611260440 in words is "twenty-one billion, six hundred eleven million, two hundred sixty thousand, four hundred forty".