21002212121228 has 72 divisors (see below), whose sum is σ = 40905780305040. Its totient is φ = 9379105948800.

The previous prime is 21002212121227. The next prime is 21002212121257. The reversal of 21002212121228 is 82212121220012.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a junction number, because it is equal to n+sod(n) for n = 21002212121197 and 21002212121206.

It is not an unprimeable number, because it can be changed into a prime (21002212121221) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 338829143 + ... + 338891121.

It is an arithmetic number, because the mean of its divisors is an integer number (568135837570).

Almost surely, 2^{21002212121228} is an apocalyptic number.

It is an amenable number.

21002212121228 is a deficient number, since it is larger than the sum of its proper divisors (19903568183812).

21002212121228 is a wasteful number, since it uses less digits than its factorization.

21002212121228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68839 (or 68806 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 26.

The spelling of 21002212121228 in words is "twenty-one trillion, two billion, two hundred twelve million, one hundred twenty-one thousand, two hundred twenty-eight".