21750523 has 2 divisors, whose sum is σ = 21750524. Its totient is φ = 21750522.

The previous prime is 21750503. The next prime is 21750529. The reversal of 21750523 is 32505712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21750523 - 2⁹ = 21750011 is a prime.

It is not a weakly prime, because it can be changed into another prime (21750529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10875261 + 10875262.

It is an arithmetic number, because the mean of its divisors is an integer number (10875262).

Almost surely, 2^21750523 is an apocalyptic number.

21750523 is a deficient number, since it is larger than the sum of its proper divisors (1).

21750523 is an equidigital number, since it uses as much as digits as its factorization.

21750523 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2100, while the sum is 25.

The square root of 21750523 is about 4663.7455976929. The cubic root of 21750523 is about 279.1407459510.

The spelling of 21750523 in words is "twenty-one million, seven hundred fifty thousand, five hundred twenty-three".