21226765188 has 12 divisors (see below), whose sum is σ = 49529118800. Its totient is φ = 7075588392.

The previous prime is 21226765187. The next prime is 21226765193. The reversal of 21226765188 is 88156762212.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (21226765187) 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, 884448538 + ... + 884448561.

Almost surely, 2^21226765188 is an apocalyptic number.

It is an amenable number.

21226765188 is an abundant number, since it is smaller than the sum of its proper divisors (28302353612).

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

21226765188 is a wasteful number, since it uses less digits than its factorization.

21226765188 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1768897106 (or 1768897104 counting only the distinct ones).

The product of its digits is 645120, while the sum is 48.

The spelling of 21226765188 in words is "twenty-one billion, two hundred twenty-six million, seven hundred sixty-five thousand, one hundred eighty-eight".