21523753 has 2 divisors, whose sum is σ = 21523754. Its totient is φ = 21523752.

The previous prime is 21523741. The next prime is 21523763. The reversal of 21523753 is 35732512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16104169 + 5419584 = 4013^2 + 2328^2 .

It is a cyclic number.

It is not a de Polignac number, because 21523753 - 2¹³ = 21515561 is a prime.

It is not a weakly prime, because it can be changed into another prime (21523763) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10761876 + 10761877.

It is an arithmetic number, because the mean of its divisors is an integer number (10761877).

Almost surely, 2^21523753 is an apocalyptic number.

It is an amenable number.

21523753 is a deficient number, since it is larger than the sum of its proper divisors (1).

21523753 is an equidigital number, since it uses as much as digits as its factorization.

21523753 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6300, while the sum is 28.

The square root of 21523753 is about 4639.3698925608. The cubic root of 21523753 is about 278.1672518059.

The spelling of 21523753 in words is "twenty-one million, five hundred twenty-three thousand, seven hundred fifty-three".