21503149 has 2 divisors, whose sum is σ = 21503150. Its totient is φ = 21503148.

The previous prime is 21503129. The next prime is 21503159. The reversal of 21503149 is 94130512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15288100 + 6215049 = 3910^2 + 2493^2 .

It is a cyclic number.

It is not a de Polignac number, because 21503149 - 2¹¹ = 21501101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21503129) 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, 10751574 + 10751575.

It is an arithmetic number, because the mean of its divisors is an integer number (10751575).

Almost surely, 2^21503149 is an apocalyptic number.

It is an amenable number.

21503149 is a deficient number, since it is larger than the sum of its proper divisors (1).

21503149 is an equidigital number, since it uses as much as digits as its factorization.

21503149 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 21503149 is about 4637.1488007180. The cubic root of 21503149 is about 278.0784632654.

The spelling of 21503149 in words is "twenty-one million, five hundred three thousand, one hundred forty-nine".