21432493 has 2 divisors, whose sum is σ = 21432494. Its totient is φ = 21432492.

The previous prime is 21432473. The next prime is 21432539. The reversal of 21432493 is 39423412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20820969 + 611524 = 4563^2 + 782^2 .

It is a cyclic number.

It is not a de Polignac number, because 21432493 - 2¹⁷ = 21301421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21432403) 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, 10716246 + 10716247.

It is an arithmetic number, because the mean of its divisors is an integer number (10716247).

Almost surely, 2^21432493 is an apocalyptic number.

It is an amenable number.

21432493 is a deficient number, since it is larger than the sum of its proper divisors (1).

21432493 is an equidigital number, since it uses as much as digits as its factorization.

21432493 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 28.

The square root of 21432493 is about 4629.5240576111. The cubic root of 21432493 is about 277.7735548810.

The spelling of 21432493 in words is "twenty-one million, four hundred thirty-two thousand, four hundred ninety-three".