21738161 has 8 divisors (see below), whose sum is σ = 22694400. Its totient is φ = 20797920.

The previous prime is 21738133. The next prime is 21738179. The reversal of 21738161 is 16183712.

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 21738161 - 2⁶ = 21738097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21738131) 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 7 ways as a sum of consecutive naturals, for example, 1181 + ... + 6698.

It is an arithmetic number, because the mean of its divisors is an integer number (2836800).

Almost surely, 2^21738161 is an apocalyptic number.

It is an amenable number.

21738161 is a deficient number, since it is larger than the sum of its proper divisors (956239).

21738161 is an equidigital number, since it uses as much as digits as its factorization.

21738161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7999.

The product of its digits is 2016, while the sum is 29.

The square root of 21738161 is about 4662.4200797440. The cubic root of 21738161 is about 279.0878523286.

The spelling of 21738161 in words is "twenty-one million, seven hundred thirty-eight thousand, one hundred sixty-one".