21838161 has 8 divisors (see below), whose sum is σ = 29169504. Its totient is φ = 14532800.

The previous prime is 21838153. The next prime is 21838171. The reversal of 21838161 is 16183812.

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 21838161 - 2³ = 21838153 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21838121) 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, 4440 + ... + 7961.

It is an arithmetic number, because the mean of its divisors is an integer number (3646188).

Almost surely, 2^21838161 is an apocalyptic number.

It is an amenable number.

21838161 is a deficient number, since it is larger than the sum of its proper divisors (7331343).

21838161 is a wasteful number, since it uses less digits than its factorization.

21838161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12991.

The product of its digits is 2304, while the sum is 30.

The square root of 21838161 is about 4673.1318192407. The cubic root of 21838161 is about 279.5151515666.

The spelling of 21838161 in words is "twenty-one million, eight hundred thirty-eight thousand, one hundred sixty-one".