21617927 has 2 divisors, whose sum is σ = 21617928. Its totient is φ = 21617926.

The previous prime is 21617909. The next prime is 21617969. The reversal of 21617927 is 72971612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21617927 - 2⁸ = 21617671 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21617977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10808963 + 10808964.

It is an arithmetic number, because the mean of its divisors is an integer number (10808964).

Almost surely, 2^21617927 is an apocalyptic number.

21617927 is a deficient number, since it is larger than the sum of its proper divisors (1).

21617927 is an equidigital number, since it uses as much as digits as its factorization.

21617927 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10584, while the sum is 35.

The square root of 21617927 is about 4649.5082535683. The cubic root of 21617927 is about 278.5723547886.

The spelling of 21617927 in words is "twenty-one million, six hundred seventeen thousand, nine hundred twenty-seven".