21607 has 8 divisors (see below), whose sum is σ = 24192. Its totient is φ = 19200.

The previous prime is 21601. The next prime is 21611. The reversal of 21607 is 70612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21607 - 2³ = 21599 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21601) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 507 + ... + 547.

It is an arithmetic number, because the mean of its divisors is an integer number (3024).

2²¹⁶⁰⁷ is an apocalyptic number.

21607 is a deficient number, since it is larger than the sum of its proper divisors (2585).

21607 is a wasteful number, since it uses less digits than its factorization.

21607 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89.

The product of its (nonzero) digits is 84, while the sum is 16.

The square root of 21607 is about 146.9931971215. The cubic root of 21607 is about 27.8525411140.

The spelling of 21607 in words is "twenty-one thousand, six hundred seven".