21201371 has 4 divisors (see below), whose sum is σ = 21652512. Its totient is φ = 20750232.

The previous prime is 21201347. The next prime is 21201373. The reversal of 21201371 is 17310212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21201371 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21201373) 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, 225500 + ... + 225593.

It is an arithmetic number, because the mean of its divisors is an integer number (5413128).

Almost surely, 2^21201371 is an apocalyptic number.

21201371 is a deficient number, since it is larger than the sum of its proper divisors (451141).

21201371 is an equidigital number, since it uses as much as digits as its factorization.

21201371 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 451140.

The product of its (nonzero) digits is 84, while the sum is 17.

The square root of 21201371 is about 4604.4946519678. The cubic root of 21201371 is about 276.7714667245.

Adding to 21201371 its reverse (17310212), we get a palindrome (38511583).

The spelling of 21201371 in words is "twenty-one million, two hundred one thousand, three hundred seventy-one".