21528193 has 2 divisors, whose sum is σ = 21528194. Its totient is φ = 21528192.

The previous prime is 21528173. The next prime is 21528217. The reversal of 21528193 is 39182512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21464689 + 63504 = 4633^2 + 252^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21528193 is a prime.

It is not a weakly prime, because it can be changed into another prime (21528113) 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, 10764096 + 10764097.

It is an arithmetic number, because the mean of its divisors is an integer number (10764097).

Almost surely, 2^21528193 is an apocalyptic number.

It is an amenable number.

21528193 is a deficient number, since it is larger than the sum of its proper divisors (1).

21528193 is an equidigital number, since it uses as much as digits as its factorization.

21528193 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4320, while the sum is 31.

The square root of 21528193 is about 4639.8483811435. The cubic root of 21528193 is about 278.1863776167.

The spelling of 21528193 in words is "twenty-one million, five hundred twenty-eight thousand, one hundred ninety-three".