21221101200 has 120 divisors (see below), whose sum is σ = 73207411648. Its totient is φ = 5223651840.

The previous prime is 21221101199. The next prime is 21221101201. The reversal of 21221101200 is 210112212.

It is an interprime number because it is at equal distance from previous prime (21221101199) and next prime (21221101201).

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×21221101200² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (21221101201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 664564 + ... + 695763.

Almost surely, 2^21221101200 is an apocalyptic number.

21221101200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221101200 is an abundant number, since it is smaller than the sum of its proper divisors (51986310448).

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

21221101200 is a wasteful number, since it uses less digits than its factorization.

21221101200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1360361 (or 1360350 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21221101200 its reverse (210112212), we get a palindrome (21431213412).

The spelling of 21221101200 in words is "twenty-one billion, two hundred twenty-one million, one hundred one thousand, two hundred".