21182161 has 24 divisors (see below), whose sum is σ = 28957824. Its totient is φ = 15230880.

The previous prime is 21182159. The next prime is 21182171. The reversal of 21182161 is 16128112.

It is not a de Polignac number, because 21182161 - 2¹ = 21182159 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21182111) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5496 + ... + 8518.

It is an arithmetic number, because the mean of its divisors is an integer number (1206576).

Almost surely, 2^21182161 is an apocalyptic number.

It is an amenable number.

21182161 is a deficient number, since it is larger than the sum of its proper divisors (7775663).

21182161 is a wasteful number, since it uses less digits than its factorization.

21182161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3061 (or 3054 counting only the distinct ones).

The product of its digits is 192, while the sum is 22.

The square root of 21182161 is about 4602.4081739889. The cubic root of 21182161 is about 276.6878497031.

The spelling of 21182161 in words is "twenty-one million, one hundred eighty-two thousand, one hundred sixty-one".