21655223442210 has 128 divisors (see below), whose sum is σ = 53737957785600. Its totient is φ = 5579192021760.

The previous prime is 21655223442043. The next prime is 21655223442211. The reversal of 21655223442210 is 1224432255612.

It is not an unprimeable number, because it can be changed into a prime (21655223442211) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2237336151 + ... + 2237345829.

It is an arithmetic number, because the mean of its divisors is an integer number (419827795200).

Almost surely, 2^{21655223442210} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21655223442210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26868978892800).

21655223442210 is an abundant number, since it is smaller than the sum of its proper divisors (32082734343390).

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

21655223442210 is a wasteful number, since it uses less digits than its factorization.

21655223442210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13456.

The product of its (nonzero) digits is 230400, while the sum is 39.

Adding to 21655223442210 its reverse (1224432255612), we get a palindrome (22879655697822).

The spelling of 21655223442210 in words is "twenty-one trillion, six hundred fifty-five billion, two hundred twenty-three million, four hundred forty-two thousand, two hundred ten".