21328607 has 4 divisors (see below), whose sum is σ = 21464616. Its totient is φ = 21192600.

The previous prime is 21328603. The next prime is 21328609. The reversal of 21328607 is 70682312.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21328607 - 2² = 21328603 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21328607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21328603) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67769 + ... + 68082.

It is an arithmetic number, because the mean of its divisors is an integer number (5366154).

Almost surely, 2^21328607 is an apocalyptic number.

21328607 is a deficient number, since it is larger than the sum of its proper divisors (136009).

21328607 is a wasteful number, since it uses less digits than its factorization.

21328607 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136008.

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 21328607 is about 4618.2904845841. The cubic root of 21328607 is about 277.3240266244.

The spelling of 21328607 in words is "twenty-one million, three hundred twenty-eight thousand, six hundred seven".