21000102021220 has 48 divisors (see below), whose sum is σ = 50517182919168. Its totient is φ = 7183329540480.

The previous prime is 21000102021211. The next prime is 21000102021233. The reversal of 21000102021220 is 2212020100012.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21000102021220.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 173954427 + ... + 174075106.

It is an arithmetic number, because the mean of its divisors is an integer number (1052441310816).

Almost surely, 2^{21000102021220} is an apocalyptic number.

21000102021220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000102021220 is an abundant number, since it is smaller than the sum of its proper divisors (29517080897948).

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

21000102021220 is a wasteful number, since it uses less digits than its factorization.

21000102021220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 348029980 (or 348029978 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21000102021220 its reverse (2212020100012), we get a palindrome (23212122121232).

The spelling of 21000102021220 in words is "twenty-one trillion, one hundred two million, twenty-one thousand, two hundred twenty".