21609007 has 8 divisors (see below), whose sum is σ = 24724256. Its totient is φ = 18500832.

The previous prime is 21608987. The next prime is 21609011. The reversal of 21609007 is 70090612.

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

It is not a de Polignac number, because 21609007 - 2¹⁹ = 21084719 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 (21609017) 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, 10213 + ... + 12145.

It is an arithmetic number, because the mean of its divisors is an integer number (3090532).

Almost surely, 2^21609007 is an apocalyptic number.

21609007 is a deficient number, since it is larger than the sum of its proper divisors (3115249).

21609007 is a wasteful number, since it uses less digits than its factorization.

21609007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3537.

The product of its (nonzero) digits is 756, while the sum is 25.

The square root of 21609007 is about 4648.5489133707. The cubic root of 21609007 is about 278.5340346288.

Adding to 21609007 its reverse (70090612), we get a palindrome (91699619).

The spelling of 21609007 in words is "twenty-one million, six hundred nine thousand, seven".