21221440100 has 144 divisors (see below), whose sum is σ = 56751784320. Its totient is φ = 6724684800.

The previous prime is 21221440091. The next prime is 21221440117. The reversal of 21221440100 is 104412212.

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, 525842 + ... + 564758.

Almost surely, 2^21221440100 is an apocalyptic number.

21221440100 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 21221440100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28375892160).

21221440100 is an abundant number, since it is smaller than the sum of its proper divisors (35530344220).

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

21221440100 is a wasteful number, since it uses less digits than its factorization.

21221440100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38998 (or 38991 counting only the distinct ones).

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

Adding to 21221440100 its reverse (104412212), we get a palindrome (21325852312).

The spelling of 21221440100 in words is "twenty-one billion, two hundred twenty-one million, four hundred forty thousand, one hundred".