21301205 has 8 divisors (see below), whose sum is σ = 25654104. Its totient is φ = 16979200.

The previous prime is 21301201. The next prime is 21301219. The reversal of 21301205 is 50210312.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3845521 + 17455684 = 1961^2 + 4178^2 .

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

It is not a de Polignac number, because 21301205 - 2² = 21301201 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21301205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21301201) 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, 6176 + ... + 8985.

It is an arithmetic number, because the mean of its divisors is an integer number (3206763).

Almost surely, 2^21301205 is an apocalyptic number.

It is an amenable number.

21301205 is a deficient number, since it is larger than the sum of its proper divisors (4352899).

21301205 is a wasteful number, since it uses less digits than its factorization.

21301205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15447.

The product of its (nonzero) digits is 60, while the sum is 14.

The square root of 21301205 is about 4615.3228489457. The cubic root of 21301205 is about 277.2052113999.

Adding to 21301205 its reverse (50210312), we get a palindrome (71511517).

The spelling of 21301205 in words is "twenty-one million, three hundred one thousand, two hundred five".