21339659 has 4 divisors (see below), whose sum is σ = 23279640. Its totient is φ = 19399680.

The previous prime is 21339649. The next prime is 21339671. The reversal of 21339659 is 95693312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21339659 - 2¹² = 21335563 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21339629) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 969974 + ... + 969995.

It is an arithmetic number, because the mean of its divisors is an integer number (5819910).

Almost surely, 2^21339659 is an apocalyptic number.

21339659 is a deficient number, since it is larger than the sum of its proper divisors (1939981).

21339659 is a wasteful number, since it uses less digits than its factorization.

21339659 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1939980.

The product of its digits is 43740, while the sum is 38.

The square root of 21339659 is about 4619.4868762667. The cubic root of 21339659 is about 277.3719193582.

The spelling of 21339659 in words is "twenty-one million, three hundred thirty-nine thousand, six hundred fifty-nine".