21188149 has 2 divisors, whose sum is σ = 21188150. Its totient is φ = 21188148.

The previous prime is 21188113. The next prime is 21188179. The reversal of 21188149 is 94188112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15944049 + 5244100 = 3993^2 + 2290^2 .

It is a cyclic number.

It is not a de Polignac number, because 21188149 - 2¹⁹ = 20663861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21188179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10594074 + 10594075.

It is an arithmetic number, because the mean of its divisors is an integer number (10594075).

Almost surely, 2^21188149 is an apocalyptic number.

It is an amenable number.

21188149 is a deficient number, since it is larger than the sum of its proper divisors (1).

21188149 is an equidigital number, since it uses as much as digits as its factorization.

21188149 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4608, while the sum is 34.

The square root of 21188149 is about 4603.0586570236. The cubic root of 21188149 is about 276.7139196076.

The spelling of 21188149 in words is "twenty-one million, one hundred eighty-eight thousand, one hundred forty-nine".