21307201 has 6 divisors (see below), whose sum is σ = 21678002. Its totient is φ = 20942640.

The previous prime is 21307193. The next prime is 21307229. The reversal of 21307201 is 10270312.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 14258176 + 7049025 = 3776^2 + 2655^2 .

It is not a de Polignac number, because 21307201 - 2³ = 21307193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21307271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 421 + ... + 6541.

Almost surely, 2^21307201 is an apocalyptic number.

It is an amenable number.

21307201 is a deficient number, since it is larger than the sum of its proper divisors (370801).

21307201 is an frugal number, since it uses more digits than its factorization.

21307201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6239 (or 6180 counting only the distinct ones).

The product of its (nonzero) digits is 84, while the sum is 16.

The square root of 21307201 is about 4615.9723786002. The cubic root of 21307201 is about 277.2312187943.

Adding to 21307201 its reverse (10270312), we get a palindrome (31577513).

The spelling of 21307201 in words is "twenty-one million, three hundred seven thousand, two hundred one".