21855070680 has 128 divisors (see below), whose sum is σ = 67805337600. Its totient is φ = 5629593600.

The previous prime is 21855070639. The next prime is 21855070697. The reversal of 21855070680 is 8607055812.

It is a super-2 number, since 2×21855070680² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2118976 + ... + 2129264.

It is an arithmetic number, because the mean of its divisors is an integer number (529729200).

Almost surely, 2^21855070680 is an apocalyptic number.

21855070680 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 21855070680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33902668800).

21855070680 is an abundant number, since it is smaller than the sum of its proper divisors (45950266920).

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

21855070680 is a wasteful number, since it uses less digits than its factorization.

21855070680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10905 (or 10901 counting only the distinct ones).

The product of its (nonzero) digits is 134400, while the sum is 42.

The spelling of 21855070680 in words is "twenty-one billion, eight hundred fifty-five million, seventy thousand, six hundred eighty".