21605151760 has 160 divisors (see below), whose sum is σ = 54594362880. Its totient is φ = 7920254976.

The previous prime is 21605151751. The next prime is 21605151773. The reversal of 21605151760 is 6715150612.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14509096 + ... + 14510584.

It is an arithmetic number, because the mean of its divisors is an integer number (341214768).

Almost surely, 2^21605151760 is an apocalyptic number.

21605151760 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 21605151760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27297181440).

21605151760 is an abundant number, since it is smaller than the sum of its proper divisors (32989211120).

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

21605151760 is a wasteful number, since it uses less digits than its factorization.

21605151760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1793 (or 1787 counting only the distinct ones).

The product of its (nonzero) digits is 12600, while the sum is 34.

The spelling of 21605151760 in words is "twenty-one billion, six hundred five million, one hundred fifty-one thousand, seven hundred sixty".