21871199 has 12 divisors (see below), whose sum is σ = 25613064. Its totient is φ = 18620784.

The previous prime is 21871169. The next prime is 21871207. The reversal of 21871199 is 99117812.

It is not a de Polignac number, because 21871199 - 2¹² = 21867103 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 (21871159) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6272 + ... + 9114.

It is an arithmetic number, because the mean of its divisors is an integer number (2134422).

Almost surely, 2^21871199 is an apocalyptic number.

21871199 is a deficient number, since it is larger than the sum of its proper divisors (3741865).

21871199 is a wasteful number, since it uses less digits than its factorization.

21871199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3014 (or 3007 counting only the distinct ones).

The product of its digits is 9072, while the sum is 38.

The square root of 21871199 is about 4676.6653718221. The cubic root of 21871199 is about 279.6560359662.

It can be divided in two parts, 218 and 71199, that added together give a palindrome (71417).

The spelling of 21871199 in words is "twenty-one million, eight hundred seventy-one thousand, one hundred ninety-nine".