21002444100 has 144 divisors (see below), whose sum is σ = 73657160640. Its totient is φ = 5091494400.

The previous prime is 21002444069. The next prime is 21002444129. The reversal of 21002444100 is 144420012.

21002444100 is a `hidden beast` number, since 2 + 10 + 0 + 244 + 410 + 0 = 666.

It is a super-2 number, since 2×21002444100² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

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, 323877 + ... + 383276.

It is an arithmetic number, because the mean of its divisors is an integer number (511508060).

Almost surely, 2^21002444100 is an apocalyptic number.

21002444100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21002444100 is an abundant number, since it is smaller than the sum of its proper divisors (52654716540).

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

21002444100 is a wasteful number, since it uses less digits than its factorization.

21002444100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 707187 (or 707174 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

Adding to 21002444100 its reverse (144420012), we get a palindrome (21146864112).

The spelling of 21002444100 in words is "twenty-one billion, two million, four hundred forty-four thousand, one hundred".