21432075 has 24 divisors (see below), whose sum is σ = 40497408. Its totient is φ = 9797280.

The previous prime is 21432023. The next prime is 21432077. The reversal of 21432075 is 57023412.

It is not a de Polignac number, because 21432075 - 2¹⁵ = 21399307 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21432077) 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 in 23 ways as a sum of consecutive naturals, for example, 19887 + ... + 20936.

It is an arithmetic number, because the mean of its divisors is an integer number (1687392).

Almost surely, 2^21432075 is an apocalyptic number.

21432075 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21432075 is a deficient number, since it is larger than the sum of its proper divisors (19065333).

21432075 is a wasteful number, since it uses less digits than its factorization.

21432075 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40843 (or 40838 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 24.

The square root of 21432075 is about 4629.4789123615. The cubic root of 21432075 is about 277.7717490543.

Adding to 21432075 its reverse (57023412), we get a palindrome (78455487).

The spelling of 21432075 in words is "twenty-one million, four hundred thirty-two thousand, seventy-five".