21002003120 has 40 divisors (see below), whose sum is σ = 55805324064. Its totient is φ = 7200686592.

The previous prime is 21002003119. The next prime is 21002003123. The reversal of 21002003120 is 2130020012.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (21002003123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18751229 + ... + 18752348.

Almost surely, 2^21002003120 is an apocalyptic number.

21002003120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21002003120 is an abundant number, since it is smaller than the sum of its proper divisors (34803320944).

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

21002003120 is a wasteful number, since it uses less digits than its factorization.

21002003120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37503597 (or 37503591 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 11.

Adding to 21002003120 its reverse (2130020012), we get a palindrome (23132023132).

The spelling of 21002003120 in words is "twenty-one billion, two million, three thousand, one hundred twenty".