21519149 has 2 divisors, whose sum is σ = 21519150. Its totient is φ = 21519148.

The previous prime is 21519143. The next prime is 21519151. The reversal of 21519149 is 94191512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13213225 + 8305924 = 3635^2 + 2882^2 .

It is a cyclic number.

It is not a de Polignac number, because 21519149 - 2¹⁶ = 21453613 is a prime.

It is a Sophie Germain prime.

Together with 21519151, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21519143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10759574 + 10759575.

It is an arithmetic number, because the mean of its divisors is an integer number (10759575).

Almost surely, 2^21519149 is an apocalyptic number.

It is an amenable number.

21519149 is a deficient number, since it is larger than the sum of its proper divisors (1).

21519149 is an equidigital number, since it uses as much as digits as its factorization.

21519149 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3240, while the sum is 32.

The square root of 21519149 is about 4638.8736779524. The cubic root of 21519149 is about 278.1474167683.

It can be divided in two parts, 2 and 1519149, that added together give a palindrome (1519151).

The spelling of 21519149 in words is "twenty-one million, five hundred nineteen thousand, one hundred forty-nine".