21075623 has 2 divisors, whose sum is σ = 21075624. Its totient is φ = 21075622.

The previous prime is 21075601. The next prime is 21075641. The reversal of 21075623 is 32657012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21075623 - 2⁶ = 21075559 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21075592 and 21075601.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21075653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10537811 + 10537812.

It is an arithmetic number, because the mean of its divisors is an integer number (10537812).

Almost surely, 2^21075623 is an apocalyptic number.

21075623 is a deficient number, since it is larger than the sum of its proper divisors (1).

21075623 is an equidigital number, since it uses as much as digits as its factorization.

21075623 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2520, while the sum is 26.

The square root of 21075623 is about 4590.8194257670. The cubic root of 21075623 is about 276.2231925284.

The spelling of 21075623 in words is "twenty-one million, seventy-five thousand, six hundred twenty-three".