21507532 has 6 divisors (see below), whose sum is σ = 37638188. Its totient is φ = 10753764.

The previous prime is 21507527. The next prime is 21507539. The reversal of 21507532 is 23570512.

It is a junction number, because it is equal to n+sod(n) for n = 21507497 and 21507506.

It is not an unprimeable number, because it can be changed into a prime (21507539) 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 as a sum of consecutive naturals, namely, 2688438 + ... + 2688445.

Almost surely, 2^21507532 is an apocalyptic number.

It is an amenable number.

21507532 is a deficient number, since it is larger than the sum of its proper divisors (16130656).

21507532 is a wasteful number, since it uses less digits than its factorization.

21507532 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5376887 (or 5376885 counting only the distinct ones).

The product of its (nonzero) digits is 2100, while the sum is 25.

The square root of 21507532 is about 4637.6213730748. The cubic root of 21507532 is about 278.0973556162.

The spelling of 21507532 in words is "twenty-one million, five hundred seven thousand, five hundred thirty-two".