21585668071680 has 1008 divisors, whose sum is σ = 81729591035904. Its totient is φ = 5451630428160.

The previous prime is 21585668071619. The next prime is 21585668071811. The reversal of 21585668071680 is 8617086658512.

21585668071680 is a `hidden beast` number, since 2 + 1 + 5 + 8 + 566 + 8 + 0 + 7 + 1 + 68 + 0 = 666.

It is a super-2 number, since 2×21585668071680² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 1359547902 + ... + 1359563778.

It is an arithmetic number, because the mean of its divisors is an integer number (81080943488).

Almost surely, 2^{21585668071680} is an apocalyptic number.

21585668071680 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 21585668071680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40864795517952).

21585668071680 is an abundant number, since it is smaller than the sum of its proper divisors (60143922964224).

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

21585668071680 is an equidigital number, since it uses as much as digits as its factorization.

21585668071680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15994 (or 15965 counting only the distinct ones).

The product of its (nonzero) digits is 38707200, while the sum is 63.

The spelling of 21585668071680 in words is "twenty-one trillion, five hundred eighty-five billion, six hundred sixty-eight million, seventy-one thousand, six hundred eighty".