21331226217 has 16 divisors (see below), whose sum is σ = 32517411840. Its totient is φ = 12184514832.

The previous prime is 21331226209. The next prime is 21331226233. The reversal of 21331226217 is 71262213312.

It is not a de Polignac number, because 21331226217 - 2³ = 21331226209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21331221217) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 142773 + ... + 251090.

It is an arithmetic number, because the mean of its divisors is an integer number (2032338240).

Almost surely, 2^21331226217 is an apocalyptic number.

It is an amenable number.

21331226217 is a deficient number, since it is larger than the sum of its proper divisors (11186185623).

21331226217 is a wasteful number, since it uses less digits than its factorization.

21331226217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396452.

The product of its digits is 6048, while the sum is 30.

Adding to 21331226217 its reverse (71262213312), we get a palindrome (92593439529).

The spelling of 21331226217 in words is "twenty-one billion, three hundred thirty-one million, two hundred twenty-six thousand, two hundred seventeen".