21110871 has 4 divisors (see below), whose sum is σ = 28147832. Its totient is φ = 14073912.

The previous prime is 21110867. The next prime is 21110879. The reversal of 21110871 is 17801112.

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

It is not a de Polignac number, because 21110871 - 2² = 21110867 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 (21110879) 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, 3518476 + ... + 3518481.

It is an arithmetic number, because the mean of its divisors is an integer number (7036958).

Almost surely, 2^21110871 is an apocalyptic number.

21110871 is a deficient number, since it is larger than the sum of its proper divisors (7036961).

21110871 is an equidigital number, since it uses as much as digits as its factorization.

21110871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7036960.

The product of its (nonzero) digits is 112, while the sum is 21.

The square root of 21110871 is about 4594.6567880528. The cubic root of 21110871 is about 276.3770969118.

Adding to 21110871 its reverse (17801112), we get a palindrome (38911983).

The spelling of 21110871 in words is "twenty-one million, one hundred ten thousand, eight hundred seventy-one".