21138163 has 2 divisors, whose sum is σ = 21138164. Its totient is φ = 21138162.

The previous prime is 21138133. The next prime is 21138179. The reversal of 21138163 is 36183112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21138163 is a prime.

It is not a weakly prime, because it can be changed into another prime (21138113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10569081 + 10569082.

It is an arithmetic number, because the mean of its divisors is an integer number (10569082).

Almost surely, 2^21138163 is an apocalyptic number.

21138163 is a deficient number, since it is larger than the sum of its proper divisors (1).

21138163 is an equidigital number, since it uses as much as digits as its factorization.

21138163 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 25.

The square root of 21138163 is about 4597.6258003452. The cubic root of 21138163 is about 276.4961451436.

The spelling of 21138163 in words is "twenty-one million, one hundred thirty-eight thousand, one hundred sixty-three".