21031532 has 6 divisors (see below), whose sum is σ = 36805188. Its totient is φ = 10515764.

The previous prime is 21031531. The next prime is 21031559. The reversal of 21031532 is 23513012.

It is a self number, because there is not a number n which added to its sum of digits gives 21031532.

It is not an unprimeable number, because it can be changed into a prime (21031531) 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, 2628938 + ... + 2628945.

It is an arithmetic number, because the mean of its divisors is an integer number (6134198).

Almost surely, 2^21031532 is an apocalyptic number.

It is an amenable number.

21031532 is a deficient number, since it is larger than the sum of its proper divisors (15773656).

21031532 is a wasteful number, since it uses less digits than its factorization.

21031532 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5257887 (or 5257885 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 21031532 is about 4586.0148277126. The cubic root of 21031532 is about 276.0304349270.

Adding to 21031532 its reverse (23513012), we get a palindrome (44544544).

The spelling of 21031532 in words is "twenty-one million, thirty-one thousand, five hundred thirty-two".