21075689 has 2 divisors, whose sum is σ = 21075690. Its totient is φ = 21075688.

The previous prime is 21075679. The next prime is 21075697. The reversal of 21075689 is 98657012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20403289 + 672400 = 4517^2 + 820^2 .

It is a cyclic number.

It is not a de Polignac number, because 21075689 - 2⁸ = 21075433 is a prime.

It is not a weakly prime, because it can be changed into another prime (21075679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10537844 + 10537845.

It is an arithmetic number, because the mean of its divisors is an integer number (10537845).

Almost surely, 2^21075689 is an apocalyptic number.

It is an amenable number.

21075689 is a deficient number, since it is larger than the sum of its proper divisors (1).

21075689 is an equidigital number, since it uses as much as digits as its factorization.

21075689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30240, while the sum is 38.

The square root of 21075689 is about 4590.8266140206. The cubic root of 21075689 is about 276.2234808665.

The spelling of 21075689 in words is "twenty-one million, seventy-five thousand, six hundred eighty-nine".