21532156 has 6 divisors (see below), whose sum is σ = 37681280. Its totient is φ = 10766076.

The previous prime is 21532097. The next prime is 21532169. The reversal of 21532156 is 65123512.

It is a self number, because there is not a number n which added to its sum of digits gives 21532156.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2691516 + ... + 2691523.

Almost surely, 2^21532156 is an apocalyptic number.

It is an amenable number.

21532156 is a deficient number, since it is larger than the sum of its proper divisors (16149124).

21532156 is a wasteful number, since it uses less digits than its factorization.

21532156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5383043 (or 5383041 counting only the distinct ones).

The product of its digits is 1800, while the sum is 25.

The square root of 21532156 is about 4640.2754228602. The cubic root of 21532156 is about 278.2034464742.

Adding to 21532156 its reverse (65123512), we get a palindrome (86655668).

The spelling of 21532156 in words is "twenty-one million, five hundred thirty-two thousand, one hundred fifty-six".