21367609 has 8 divisors (see below), whose sum is σ = 22612640. Its totient is φ = 20134656.

The previous prime is 21367607. The next prime is 21367613. The reversal of 21367609 is 90676312.

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 21367609 - 2¹ = 21367607 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21367607) 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 7 ways as a sum of consecutive naturals, for example, 754 + ... + 6580.

It is an arithmetic number, because the mean of its divisors is an integer number (2826580).

Almost surely, 2^21367609 is an apocalyptic number.

It is an amenable number.

21367609 is a deficient number, since it is larger than the sum of its proper divisors (1245031).

21367609 is a wasteful number, since it uses less digits than its factorization.

21367609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6039.

The product of its (nonzero) digits is 13608, while the sum is 34.

The square root of 21367609 is about 4622.5111141024. The cubic root of 21367609 is about 277.4929641373.

The spelling of 21367609 in words is "twenty-one million, three hundred sixty-seven thousand, six hundred nine".