21188029 has 2 divisors, whose sum is σ = 21188030. Its totient is φ = 21188028.

The previous prime is 21188003. The next prime is 21188053. The reversal of 21188029 is 92088112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14822500 + 6365529 = 3850^2 + 2523^2 .

It is a cyclic number.

It is not a de Polignac number, because 21188029 - 2¹¹ = 21185981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21188099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10594014 + 10594015.

It is an arithmetic number, because the mean of its divisors is an integer number (10594015).

Almost surely, 2^21188029 is an apocalyptic number.

It is an amenable number.

21188029 is a deficient number, since it is larger than the sum of its proper divisors (1).

21188029 is an equidigital number, since it uses as much as digits as its factorization.

21188029 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 21188029 is about 4603.0456221941. The cubic root of 21188029 is about 276.7133972129.

The spelling of 21188029 in words is "twenty-one million, one hundred eighty-eight thousand, twenty-nine".