21732012 has 18 divisors (see below), whose sum is σ = 54933788. Its totient is φ = 7243992.

The previous prime is 21731999. The next prime is 21732013. The reversal of 21732012 is 21023712.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21732013) by changing a digit.

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 in 5 ways as a sum of consecutive naturals, for example, 301798 + ... + 301869.

Almost surely, 2^21732012 is an apocalyptic number.

It is an amenable number.

21732012 is an abundant number, since it is smaller than the sum of its proper divisors (33201776).

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

21732012 is a wasteful number, since it uses less digits than its factorization.

21732012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 603677 (or 603672 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 21732012 is about 4661.7606116145. The cubic root of 21732012 is about 279.0615349684.

Adding to 21732012 its reverse (21023712), we get a palindrome (42755724).

The spelling of 21732012 in words is "twenty-one million, seven hundred thirty-two thousand, twelve".