21605152 has 12 divisors (see below), whose sum is σ = 42535206. Its totient is φ = 10802560.

The previous prime is 21605123. The next prime is 21605159. The reversal of 21605152 is 25150612.

It can be written as a sum of positive squares in only one way, i.e., 21566736 + 38416 = 4644^2 + 196^2 .

It is not an unprimeable number, because it can be changed into a prime (21605159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 337549 + ... + 337612.

Almost surely, 2^21605152 is an apocalyptic number.

It is an amenable number.

21605152 is a deficient number, since it is larger than the sum of its proper divisors (20930054).

21605152 is an equidigital number, since it uses as much as digits as its factorization.

21605152 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 675171 (or 675163 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 22.

The square root of 21605152 is about 4648.1342493521. The cubic root of 21605152 is about 278.5174703544.

Adding to 21605152 its reverse (25150612), we get a palindrome (46755764).

The spelling of 21605152 in words is "twenty-one million, six hundred five thousand, one hundred fifty-two".