21375617 has 2 divisors, whose sum is σ = 21375618. Its totient is φ = 21375616.

The previous prime is 21375611. The next prime is 21375631. The reversal of 21375617 is 71657312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13075456 + 8300161 = 3616^2 + 2881^2 .

It is a cyclic number.

It is not a de Polignac number, because 21375617 - 2²² = 17181313 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21375611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10687808 + 10687809.

It is an arithmetic number, because the mean of its divisors is an integer number (10687809).

Almost surely, 2^21375617 is an apocalyptic number.

It is an amenable number.

21375617 is a deficient number, since it is larger than the sum of its proper divisors (1).

21375617 is an equidigital number, since it uses as much as digits as its factorization.

21375617 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8820, while the sum is 32.

The square root of 21375617 is about 4623.3772288231. The cubic root of 21375617 is about 277.5276254185.

The spelling of 21375617 in words is "twenty-one million, three hundred seventy-five thousand, six hundred seventeen".