21585945001320 has 1536 divisors, whose sum is σ = 86306508288000. Its totient is φ = 4575252971520.

The previous prime is 21585945001303. The next prime is 21585945001351. The reversal of 21585945001320 is 2310054958512.

21585945001320 is a `hidden beast` number, since 2 + 1 + 5 + 8 + 5 + 9 + 4 + 500 + 132 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 73672167094 + ... + 73672167386.

It is an arithmetic number, because the mean of its divisors is an integer number (56189133000).

Almost surely, 2^{21585945001320} is an apocalyptic number.

21585945001320 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 21585945001320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43153254144000).

21585945001320 is an abundant number, since it is smaller than the sum of its proper divisors (64720563286680).

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

21585945001320 is a wasteful number, since it uses less digits than its factorization.

21585945001320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 723 (or 716 counting only the distinct ones).

The product of its (nonzero) digits is 432000, while the sum is 45.

Adding to 21585945001320 its reverse (2310054958512), we get a palindrome (23895999959832).

The spelling of 21585945001320 in words is "twenty-one trillion, five hundred eighty-five billion, nine hundred forty-five million, one thousand, three hundred twenty".