21232505 has 8 divisors (see below), whose sum is σ = 29118912. Its totient is φ = 14559408.

The previous prime is 21232493. The next prime is 21232511. The reversal of 21232505 is 50523212.

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 21232505 - 2⁶ = 21232441 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 303287 + ... + 303356.

It is an arithmetic number, because the mean of its divisors is an integer number (3639864).

Almost surely, 2^21232505 is an apocalyptic number.

It is an amenable number.

21232505 is a deficient number, since it is larger than the sum of its proper divisors (7886407).

21232505 is an equidigital number, since it uses as much as digits as its factorization.

21232505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 606655.

The product of its (nonzero) digits is 600, while the sum is 20.

The square root of 21232505 is about 4607.8742387353. The cubic root of 21232505 is about 276.9068791669.

Adding to 21232505 its reverse (50523212), we get a palindrome (71755717).

The spelling of 21232505 in words is "twenty-one million, two hundred thirty-two thousand, five hundred five".