21420101100 has 144 divisors (see below), whose sum is σ = 62532587936. Its totient is φ = 5660928000.

The previous prime is 21420101083. The next prime is 21420101119. The reversal of 21420101100 is 110102412.

It is a happy number.

It is a super-2 number, since 2×21420101100² (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 an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 22859832 + ... + 22860768.

Almost surely, 2^21420101100 is an apocalyptic number.

21420101100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21420101100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31266293968).

21420101100 is an abundant number, since it is smaller than the sum of its proper divisors (41112486836).

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

21420101100 is a wasteful number, since it uses less digits than its factorization.

21420101100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1556 (or 1549 counting only the distinct ones).

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

Adding to 21420101100 its reverse (110102412), we get a palindrome (21530203512).

The spelling of 21420101100 in words is "twenty-one billion, four hundred twenty million, one hundred one thousand, one hundred".