21738189 has 16 divisors (see below), whose sum is σ = 33480000. Its totient is φ = 12399360.

The previous prime is 21738187. The next prime is 21738191. The reversal of 21738189 is 98183712.

It is an interprime number because it is at equal distance from previous prime (21738187) and next prime (21738191).

It is not a de Polignac number, because 21738189 - 2¹ = 21738187 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21738181) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18814 + ... + 19935.

It is an arithmetic number, because the mean of its divisors is an integer number (2092500).

Almost surely, 2^21738189 is an apocalyptic number.

It is an amenable number.

21738189 is a deficient number, since it is larger than the sum of its proper divisors (11741811).

21738189 is a wasteful number, since it uses less digits than its factorization.

21738189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38780.

The product of its digits is 24192, while the sum is 39.

The square root of 21738189 is about 4662.4230824755. The cubic root of 21738189 is about 279.0879721556.

It can be divided in two parts, 217381 and 89, that added together give a triangular number (217470 = T₆₅₉).

The spelling of 21738189 in words is "twenty-one million, seven hundred thirty-eight thousand, one hundred eighty-nine".