21339585 has 16 divisors (see below), whose sum is σ = 37937280. Its totient is φ = 11381040.

The previous prime is 21339581. The next prime is 21339587. The reversal of 21339585 is 58593312.

It is not a de Polignac number, because 21339585 - 2² = 21339581 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21339581) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 78901 + ... + 79170.

It is an arithmetic number, because the mean of its divisors is an integer number (2371080).

Almost surely, 2^21339585 is an apocalyptic number.

It is an amenable number.

21339585 is a deficient number, since it is larger than the sum of its proper divisors (16597695).

21339585 is a wasteful number, since it uses less digits than its factorization.

21339585 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158085 (or 158079 counting only the distinct ones).

The product of its digits is 32400, while the sum is 36.

The square root of 21339585 is about 4619.4788667121. The cubic root of 21339585 is about 277.3715987416.

The spelling of 21339585 in words is "twenty-one million, three hundred thirty-nine thousand, five hundred eighty-five".