21138179 has 2 divisors, whose sum is σ = 21138180. Its totient is φ = 21138178.

The previous prime is 21138163. The next prime is 21138209. The reversal of 21138179 is 97183112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21138179 - 2⁴ = 21138163 is a prime.

It is a super-2 number, since 2×21138179² = 893645222872082, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21138379) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10569089 + 10569090.

It is an arithmetic number, because the mean of its divisors is an integer number (10569090).

Almost surely, 2^21138179 is an apocalyptic number.

21138179 is a deficient number, since it is larger than the sum of its proper divisors (1).

21138179 is an equidigital number, since it uses as much as digits as its factorization.

21138179 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 32.

The square root of 21138179 is about 4597.6275403734. The cubic root of 21138179 is about 276.4962149059.

The spelling of 21138179 in words is "twenty-one million, one hundred thirty-eight thousand, one hundred seventy-nine".