21707489 has 8 divisors (see below), whose sum is σ = 21944832. Its totient is φ = 21471840.

The previous prime is 21707473. The next prime is 21707501. The reversal of 21707489 is 98470712.

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 21707489 - 2⁴ = 21707473 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21707429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 69197 + ... + 69509.

It is an arithmetic number, because the mean of its divisors is an integer number (2743104).

Almost surely, 2^21707489 is an apocalyptic number.

It is an amenable number.

21707489 is a deficient number, since it is larger than the sum of its proper divisors (237343).

21707489 is a wasteful number, since it uses less digits than its factorization.

With its predecessor (21707488) it forms a Ruth-Aaron pair, since the sum of their prime factors is the same (847).

21707489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 847.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 21707489 is about 4659.1296397503. The cubic root of 21707489 is about 278.9565285576.

The spelling of 21707489 in words is "twenty-one million, seven hundred seven thousand, four hundred eighty-nine".