21358985 has 8 divisors (see below), whose sum is σ = 25818696. Its totient is φ = 16961920.

The previous prime is 21358979. The next prime is 21358999. The reversal of 21358985 is 58985312.

It can be written as a sum of positive squares in 4 ways, for example, as 51529 + 21307456 = 227^2 + 4616^2 .

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

It is not a de Polignac number, because 21358985 - 2²² = 17164681 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14906 + ... + 16275.

It is an arithmetic number, because the mean of its divisors is an integer number (3227337).

Almost surely, 2^21358985 is an apocalyptic number.

It is an amenable number.

21358985 is a deficient number, since it is larger than the sum of its proper divisors (4459711).

21358985 is a wasteful number, since it uses less digits than its factorization.

21358985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31323.

The product of its digits is 86400, while the sum is 41.

The square root of 21358985 is about 4621.5781936477. The cubic root of 21358985 is about 277.4556269174.

The spelling of 21358985 in words is "twenty-one million, three hundred fifty-eight thousand, nine hundred eighty-five".