21101212110 has 256 divisors, whose sum is σ = 59162213376. Its totient is φ = 4769280000.

The previous prime is 21101212103. The next prime is 21101212123. The reversal of 21101212110 is 1121210112.

It is a super-2 number, since 2×21101212110² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 30536865 + ... + 30537555.

It is an arithmetic number, because the mean of its divisors is an integer number (231102396).

Almost surely, 2^21101212110 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21101212110, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29581106688).

21101212110 is an abundant number, since it is smaller than the sum of its proper divisors (38061001266).

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

21101212110 is a wasteful number, since it uses less digits than its factorization.

21101212110 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 851.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21101212110 its reverse (1121210112), we get a palindrome (22222422222).

The spelling of 21101212110 in words is "twenty-one billion, one hundred one million, two hundred twelve thousand, one hundred ten".