21118129 has 2 divisors, whose sum is σ = 21118130. Its totient is φ = 21118128.

The previous prime is 21118103. The next prime is 21118133. The reversal of 21118129 is 92181112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19158129 + 1960000 = 4377^2 + 1400^2 .

It is a cyclic number.

It is not a de Polignac number, because 21118129 - 2⁷ = 21118001 is a prime.

It is not a weakly prime, because it can be changed into another prime (21118159) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10559064 + 10559065.

It is an arithmetic number, because the mean of its divisors is an integer number (10559065).

Almost surely, 2^21118129 is an apocalyptic number.

It is an amenable number.

21118129 is a deficient number, since it is larger than the sum of its proper divisors (1).

21118129 is an equidigital number, since it uses as much as digits as its factorization.

21118129 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 288, while the sum is 25.

The square root of 21118129 is about 4595.4465506629. The cubic root of 21118129 is about 276.4087664582.

The spelling of 21118129 in words is "twenty-one million, one hundred eighteen thousand, one hundred twenty-nine".