21531152 has 20 divisors (see below), whose sum is σ = 41860416. Its totient is φ = 10728480.

The previous prime is 21531149. The next prime is 21531157. The reversal of 21531152 is 25113512.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21531157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2813 + ... + 7139.

Almost surely, 2^21531152 is an apocalyptic number.

It is an amenable number.

21531152 is a deficient number, since it is larger than the sum of its proper divisors (20329264).

21531152 is a wasteful number, since it uses less digits than its factorization.

21531152 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4646 (or 4640 counting only the distinct ones).

The product of its digits is 300, while the sum is 20.

The square root of 21531152 is about 4640.1672383654. The cubic root of 21531152 is about 278.1991223894.

Adding to 21531152 its reverse (25113512), we get a palindrome (46644664).

The spelling of 21531152 in words is "twenty-one million, five hundred thirty-one thousand, one hundred fifty-two".