21385689 has 8 divisors (see below), whose sum is σ = 30707712. Its totient is φ = 13160400.

The previous prime is 21385681. The next prime is 21385703. The reversal of 21385689 is 98658312.

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

It is not a de Polignac number, because 21385689 - 2³ = 21385681 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21385689.

It is not an unprimeable number, because it can be changed into a prime (21385681) 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, 274137 + ... + 274214.

It is an arithmetic number, because the mean of its divisors is an integer number (3838464).

Almost surely, 2^21385689 is an apocalyptic number.

It is an amenable number.

21385689 is a deficient number, since it is larger than the sum of its proper divisors (9322023).

21385689 is a wasteful number, since it uses less digits than its factorization.

21385689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 548367.

The product of its digits is 103680, while the sum is 42.

The square root of 21385689 is about 4624.4663475908. The cubic root of 21385689 is about 277.5712080875.

The spelling of 21385689 in words is "twenty-one million, three hundred eighty-five thousand, six hundred eighty-nine".