21012220222100 has 18 divisors (see below), whose sum is σ = 45596517882174. Its totient is φ = 8404888088800.

The previous prime is 21012220222073. The next prime is 21012220222127. The reversal of 21012220222100 is 122202221012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21012220222073) and next prime (21012220222127).

It can be written as a sum of positive squares in 3 ways, for example, as 472634250256 + 20539585971844 = 687484^2 + 4532062^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 105061101011 + ... + 105061101210.

It is an arithmetic number, because the mean of its divisors is an integer number (2533139882343).

Almost surely, 2^{21012220222100} is an apocalyptic number.

21012220222100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21012220222100 is an abundant number, since it is smaller than the sum of its proper divisors (24584297660074).

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

21012220222100 is a wasteful number, since it uses less digits than its factorization.

21012220222100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210122202235 (or 210122202228 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21012220222100 its reverse (122202221012), we get a palindrome (21134422443112).

The spelling of 21012220222100 in words is "twenty-one trillion, twelve billion, two hundred twenty million, two hundred twenty-two thousand, one hundred".