21605667007 has 8 divisors (see below), whose sum is σ = 21631634640. Its totient is φ = 21579718080.

The previous prime is 21605666987. The next prime is 21605667037. The reversal of 21605667007 is 70076650612.

It is a happy number.

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 21605667007 - 2⁷ = 21605666879 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 (21605667037) 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, 4249707 + ... + 4254787.

It is an arithmetic number, because the mean of its divisors is an integer number (2703954330).

Almost surely, 2^21605667007 is an apocalyptic number.

21605667007 is a deficient number, since it is larger than the sum of its proper divisors (25967633).

21605667007 is a wasteful number, since it uses less digits than its factorization.

21605667007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9353.

The product of its (nonzero) digits is 105840, while the sum is 40.

The spelling of 21605667007 in words is "twenty-one billion, six hundred five million, six hundred sixty-seven thousand, seven".