21432605 has 8 divisors (see below), whose sum is σ = 25754112. Its totient is φ = 17122768.

The previous prime is 21432601. The next prime is 21432629. The reversal of 21432605 is 50623412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21432605 - 2² = 21432601 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21432601) 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 7 ways as a sum of consecutive naturals, for example, 1832 + ... + 6798.

It is an arithmetic number, because the mean of its divisors is an integer number (3219264).

Almost surely, 2^21432605 is an apocalyptic number.

It is an amenable number.

21432605 is a deficient number, since it is larger than the sum of its proper divisors (4321507).

21432605 is an equidigital number, since it uses as much as digits as its factorization.

21432605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5835.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 21432605 is about 4629.5361538711. The cubic root of 21432605 is about 277.7740387349.

The spelling of 21432605 in words is "twenty-one million, four hundred thirty-two thousand, six hundred five".