21102102111220 has 24 divisors (see below), whose sum is σ = 47723215544424. Its totient is φ = 7791545394816.

The previous prime is 21102102111217. The next prime is 21102102111229. The reversal of 21102102111220 is 2211120120112.

It can be written as a sum of positive squares in 4 ways, for example, as 427020427024 + 20675081684196 = 653468^2 + 4546986^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21102102111194 and 21102102111203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102102111229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40580965339 + ... + 40580965858.

It is an arithmetic number, because the mean of its divisors is an integer number (1988467314351).

Almost surely, 2^{21102102111220} is an apocalyptic number.

21102102111220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21102102111220 is an abundant number, since it is smaller than the sum of its proper divisors (26621113433204).

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

21102102111220 is a wasteful number, since it uses less digits than its factorization.

21102102111220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81161931219 (or 81161931217 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21102102111220 its reverse (2211120120112), we get a palindrome (23313222231332).

The spelling of 21102102111220 in words is "twenty-one trillion, one hundred two billion, one hundred two million, one hundred eleven thousand, two hundred twenty".