21658672 has 20 divisors (see below), whose sum is σ = 47958736. Its totient is φ = 9282240.

The previous prime is 21658669. The next prime is 21658673. The reversal of 21658672 is 27685612.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21658673) 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 in 3 ways as a sum of consecutive naturals, for example, 96579 + ... + 96802.

Almost surely, 2^21658672 is an apocalyptic number.

It is an amenable number.

21658672 is an abundant number, since it is smaller than the sum of its proper divisors (26300064).

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

21658672 is a wasteful number, since it uses less digits than its factorization.

21658672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193396 (or 193390 counting only the distinct ones).

The product of its digits is 40320, while the sum is 37.

The square root of 21658672 is about 4653.8878370670. The cubic root of 21658672 is about 278.7472606593.

The spelling of 21658672 in words is "twenty-one million, six hundred fifty-eight thousand, six hundred seventy-two".