21249149 has 2 divisors, whose sum is σ = 21249150. Its totient is φ = 21249148.

The previous prime is 21249143. The next prime is 21249157. The reversal of 21249149 is 94194212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13823524 + 7425625 = 3718^2 + 2725^2 .

It is a cyclic number.

It is not a de Polignac number, because 21249149 - 2⁸ = 21248893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21249143) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10624574 + 10624575.

It is an arithmetic number, because the mean of its divisors is an integer number (10624575).

Almost surely, 2^21249149 is an apocalyptic number.

It is an amenable number.

21249149 is a deficient number, since it is larger than the sum of its proper divisors (1).

21249149 is an equidigital number, since it uses as much as digits as its factorization.

21249149 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 32.

The square root of 21249149 is about 4609.6799238125. The cubic root of 21249149 is about 276.9792153380.

The spelling of 21249149 in words is "twenty-one million, two hundred forty-nine thousand, one hundred forty-nine".