21440423100 has 72 divisors (see below), whose sum is σ = 62381007360. Its totient is φ = 5685490880.

The previous prime is 21440423077. The next prime is 21440423131. The reversal of 21440423100 is 132404412.

It is a super-2 number, since 2×21440423100² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 145932 + ... + 253331.

It is an arithmetic number, because the mean of its divisors is an integer number (866402880).

Almost surely, 2^21440423100 is an apocalyptic number.

21440423100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21440423100 is an abundant number, since it is smaller than the sum of its proper divisors (40940584260).

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

21440423100 is a wasteful number, since it uses less digits than its factorization.

21440423100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399459 (or 399452 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 21.

Adding to 21440423100 its reverse (132404412), we get a palindrome (21572827512).

The spelling of 21440423100 in words is "twenty-one billion, four hundred forty million, four hundred twenty-three thousand, one hundred".