21000220120 has 32 divisors (see below), whose sum is σ = 51545995920. Its totient is φ = 7636443520.

The previous prime is 21000220103. The next prime is 21000220121. The reversal of 21000220120 is 2102200012.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 21000220097 and 21000220106.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000220121) 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, 23863447 + ... + 23864326.

Almost surely, 2^21000220120 is an apocalyptic number.

21000220120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000220120 is an abundant number, since it is smaller than the sum of its proper divisors (30545775800).

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

21000220120 is a wasteful number, since it uses less digits than its factorization.

21000220120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47727795 (or 47727791 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 21000220120 its reverse (2102200012), we get a palindrome (23102420132).

The spelling of 21000220120 in words is "twenty-one billion, two hundred twenty thousand, one hundred twenty".