21384529 has 2 divisors, whose sum is σ = 21384530. Its totient is φ = 21384528.

The previous prime is 21384511. The next prime is 21384533. The reversal of 21384529 is 92548312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20948929 + 435600 = 4577^2 + 660^2 .

It is a cyclic number.

It is not a de Polignac number, because 21384529 - 2²¹ = 19287377 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21384494 and 21384503.

It is not a weakly prime, because it can be changed into another prime (21384509) 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, 10692264 + 10692265.

It is an arithmetic number, because the mean of its divisors is an integer number (10692265).

Almost surely, 2^21384529 is an apocalyptic number.

It is an amenable number.

21384529 is a deficient number, since it is larger than the sum of its proper divisors (1).

21384529 is an equidigital number, since it uses as much as digits as its factorization.

21384529 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17280, while the sum is 34.

The square root of 21384529 is about 4624.3409260131. The cubic root of 21384529 is about 277.5661893353.

The spelling of 21384529 in words is "twenty-one million, three hundred eighty-four thousand, five hundred twenty-nine".