21211210028 has 12 divisors (see below), whose sum is σ = 37120674360. Its totient is φ = 10605303072.

The previous prime is 21211210021. The next prime is 21211210037. The reversal of 21211210028 is 82001211212.

It is a junction number, because it is equal to n+sod(n) for n = 21211209991 and 21211210009.

It is not an unprimeable number, because it can be changed into a prime (21211210021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 174728 + ... + 270096.

It is an arithmetic number, because the mean of its divisors is an integer number (3093389530).

Almost surely, 2^21211210028 is an apocalyptic number.

It is an amenable number.

21211210028 is a deficient number, since it is larger than the sum of its proper divisors (15909464332).

21211210028 is a wasteful number, since it uses less digits than its factorization.

21211210028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150976 (or 150974 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 20.

The spelling of 21211210028 in words is "twenty-one billion, two hundred eleven million, two hundred ten thousand, twenty-eight".