21339601 has 4 divisors (see below), whose sum is σ = 21352500. Its totient is φ = 21326704.

The previous prime is 21339599. The next prime is 21339629. The reversal of 21339601 is 10693312.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8271376 + 13068225 = 2876^2 + 3615^2 .

It is a cyclic number.

It is not a de Polignac number, because 21339601 - 2¹ = 21339599 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21339671) 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 3 ways as a sum of consecutive naturals, for example, 3526 + ... + 7423.

It is an arithmetic number, because the mean of its divisors is an integer number (5338125).

Almost surely, 2^21339601 is an apocalyptic number.

It is an amenable number.

21339601 is a deficient number, since it is larger than the sum of its proper divisors (12899).

21339601 is a wasteful number, since it uses less digits than its factorization.

21339601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12898.

The product of its (nonzero) digits is 972, while the sum is 25.

The square root of 21339601 is about 4619.4805985089. The cubic root of 21339601 is about 277.3716680642.

The spelling of 21339601 in words is "twenty-one million, three hundred thirty-nine thousand, six hundred one".