21101220100000 has 72 divisors (see below), whose sum is σ = 51925460643756. Its totient is φ = 8440488000000.

The previous prime is 21101220099917. The next prime is 21101220100003. The reversal of 21101220100000 is 102210112.

It can be written as a sum of positive squares in 6 ways, for example, as 281455714576 + 20819764385424 = 530524^2 + 4562868^2 .

It is a super-2 number, since 2×21101220100000² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a self number, because there is not a number n which added to its sum of digits gives 21101220100000.

It is not an unprimeable number, because it can be changed into a prime (21101220100003) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 105406101 + ... + 105606100.

Almost surely, 2^{21101220100000} is an apocalyptic number.

21101220100000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21101220100000 is an abundant number, since it is smaller than the sum of its proper divisors (30824240543756).

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

21101220100000 is an frugal number, since it uses more digits than its factorization.

21101220100000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211012236 (or 211012208 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21101220100000 its reverse (102210112), we get a palindrome (21101322310112).

The spelling of 21101220100000 in words is "twenty-one trillion, one hundred one billion, two hundred twenty million, one hundred thousand".