21071371 has 4 divisors (see below), whose sum is σ = 21798000. Its totient is φ = 20344744.

The previous prime is 21071363. The next prime is 21071383. The reversal of 21071371 is 17317012.

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 21071371 - 2³ = 21071363 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21071321) 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, 363271 + ... + 363328.

It is an arithmetic number, because the mean of its divisors is an integer number (5449500).

Almost surely, 2^21071371 is an apocalyptic number.

21071371 is a deficient number, since it is larger than the sum of its proper divisors (726629).

21071371 is an equidigital number, since it uses as much as digits as its factorization.

21071371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 726628.

The product of its (nonzero) digits is 294, while the sum is 22.

The square root of 21071371 is about 4590.3563042535. The cubic root of 21071371 is about 276.2046152997.

Adding to 21071371 its reverse (17317012), we get a palindrome (38388383).

The spelling of 21071371 in words is "twenty-one million, seventy-one thousand, three hundred seventy-one".