21211220228 has 24 divisors (see below), whose sum is σ = 42625420320. Its totient is φ = 9134017920.

The previous prime is 21211220227. The next prime is 21211220237. The reversal of 21211220228 is 82202211212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21211220227) 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, 12685301 + ... + 12686972.

It is an arithmetic number, because the mean of its divisors is an integer number (1776059180).

Almost surely, 2^21211220228 is an apocalyptic number.

It is an amenable number.

21211220228 is an abundant number, since it is smaller than the sum of its proper divisors (21414200092).

21211220228 is a wasteful number, since it uses less digits than its factorization.

21211220228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25372307 (or 25372305 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 23.

The spelling of 21211220228 in words is "twenty-one billion, two hundred eleven million, two hundred twenty thousand, two hundred twenty-eight".