21000001101220 has 48 divisors (see below), whose sum is σ = 46023028248960. Its totient is φ = 8033799223296.

The previous prime is 21000001101193. The next prime is 21000001101239. The reversal of 21000001101220 is 2210110000012.

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 = 21000001101197 and 21000001101206.

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, 971524 + ... + 6553156.

It is an arithmetic number, because the mean of its divisors is an integer number (958813088520).

Almost surely, 2^{21000001101220} is an apocalyptic number.

21000001101220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000001101220 is an abundant number, since it is smaller than the sum of its proper divisors (25023027147740).

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

21000001101220 is a wasteful number, since it uses less digits than its factorization.

21000001101220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5589844 (or 5589842 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21000001101220 its reverse (2210110000012), we get a palindrome (23210111101232).

The spelling of 21000001101220 in words is "twenty-one trillion, one million, one hundred one thousand, two hundred twenty".