21601501560 has 192 divisors, whose sum is σ = 73592064000. Its totient is φ = 5484771072.

The previous prime is 21601501513. The next prime is 21601501601. The reversal of 21601501560 is 6510510612.

It is a happy number.

21601501560 is a `hidden beast` number, since 2 + 1 + 601 + 5 + 0 + 1 + 56 + 0 = 666.

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, 1840591 + ... + 1852289.

It is an arithmetic number, because the mean of its divisors is an integer number (383292000).

Almost surely, 2^21601501560 is an apocalyptic number.

21601501560 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 21601501560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36796032000).

21601501560 is an abundant number, since it is smaller than the sum of its proper divisors (51990562440).

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

21601501560 is a wasteful number, since it uses less digits than its factorization.

21601501560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11962 (or 11955 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The spelling of 21601501560 in words is "twenty-one billion, six hundred one million, five hundred one thousand, five hundred sixty".