21871121 has 8 divisors (see below), whose sum is σ = 22550400. Its totient is φ = 21200848.

The previous prime is 21871117. The next prime is 21871141. The reversal of 21871121 is 12117812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21871121 - 2² = 21871117 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21871141) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2855 + ... + 7203.

It is an arithmetic number, because the mean of its divisors is an integer number (2818800).

Almost surely, 2^21871121 is an apocalyptic number.

It is an amenable number.

21871121 is a deficient number, since it is larger than the sum of its proper divisors (679279).

21871121 is a wasteful number, since it uses less digits than its factorization.

21871121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4503.

The product of its digits is 224, while the sum is 23.

The square root of 21871121 is about 4676.6570325394. The cubic root of 21871121 is about 279.6557035168.

Adding to 21871121 its reverse (12117812), we get a palindrome (33988933).

The spelling of 21871121 in words is "twenty-one million, eight hundred seventy-one thousand, one hundred twenty-one".