21306032 has 40 divisors (see below), whose sum is σ = 47688912. Its totient is φ = 9113600.

The previous prime is 21306023. The next prime is 21306079. The reversal of 21306032 is 23060312.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a self number, because there is not a number n which added to its sum of digits gives 21306032.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 569 + ... + 6552.

Almost surely, 2^21306032 is an apocalyptic number.

21306032 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21306032 is an abundant number, since it is smaller than the sum of its proper divisors (26382880).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21306032 is a wasteful number, since it uses less digits than its factorization.

21306032 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7157 (or 7151 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 17.

The square root of 21306032 is about 4615.8457513223. The cubic root of 21306032 is about 277.2261486896.

Adding to 21306032 its reverse (23060312), we get a palindrome (44366344).

The spelling of 21306032 in words is "twenty-one million, three hundred six thousand, thirty-two".