21371071 has 12 divisors (see below), whose sum is σ = 22695120. Its totient is φ = 20118560.

The previous prime is 21371069. The next prime is 21371087. The reversal of 21371071 is 17017312.

It is not a de Polignac number, because 21371071 - 2¹ = 21371069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21371011) 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 11 ways as a sum of consecutive naturals, for example, 37275 + ... + 37843.

It is an arithmetic number, because the mean of its divisors is an integer number (1891260).

Almost surely, 2^21371071 is an apocalyptic number.

21371071 is a deficient number, since it is larger than the sum of its proper divisors (1324049).

21371071 is an equidigital number, since it uses as much as digits as its factorization.

21371071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 686 (or 663 counting only the distinct ones).

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

The square root of 21371071 is about 4622.8855707231. The cubic root of 21371071 is about 277.5079498845.

Adding to 21371071 its reverse (17017312), we get a palindrome (38388383).

The spelling of 21371071 in words is "twenty-one million, three hundred seventy-one thousand, seventy-one".