21838171 has 2 divisors, whose sum is σ = 21838172. Its totient is φ = 21838170.

The previous prime is 21838153. The next prime is 21838231. The reversal of 21838171 is 17183812.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21838171 - 2⁵ = 21838139 is a prime.

It is not a weakly prime, because it can be changed into another prime (21838121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10919085 + 10919086.

It is an arithmetic number, because the mean of its divisors is an integer number (10919086).

Almost surely, 2^21838171 is an apocalyptic number.

21838171 is a deficient number, since it is larger than the sum of its proper divisors (1).

21838171 is an equidigital number, since it uses as much as digits as its factorization.

21838171 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2688, while the sum is 31.

The square root of 21838171 is about 4673.1328891869. The cubic root of 21838171 is about 279.5151942312.

The spelling of 21838171 in words is "twenty-one million, eight hundred thirty-eight thousand, one hundred seventy-one".