21172345227 has 24 divisors (see below), whose sum is σ = 34813029888. Its totient is φ = 12273822000.

The previous prime is 21172345219. The next prime is 21172345253. The reversal of 21172345227 is 72254327112.

21172345227 is a `hidden beast` number, since 21 + 1 + 72 + 345 + 227 = 666.

It is not a de Polignac number, because 21172345227 - 2³ = 21172345219 is a prime.

It is a super-2 number, since 2×21172345227² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21172345191 and 21172345200.

It is not an unprimeable number, because it can be changed into a prime (21172345277) 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, 4646899 + ... + 4651452.

It is an arithmetic number, because the mean of its divisors is an integer number (1450542912).

Almost surely, 2^21172345227 is an apocalyptic number.

21172345227 is a deficient number, since it is larger than the sum of its proper divisors (13640684661).

21172345227 is a wasteful number, since it uses less digits than its factorization.

21172345227 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9298391 (or 9298388 counting only the distinct ones).

The product of its digits is 47040, while the sum is 36.

The spelling of 21172345227 in words is "twenty-one billion, one hundred seventy-two million, three hundred forty-five thousand, two hundred twenty-seven".