21042519 has 16 divisors (see below), whose sum is σ = 29913600. Its totient is φ = 13118976.

The previous prime is 21042491. The next prime is 21042533. The reversal of 21042519 is 91524012.

It is not a de Polignac number, because 21042519 - 2¹⁶ = 20976983 is a prime.

It is a super-2 number, since 2×21042519² = 885575211730722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21042319) 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 in 15 ways as a sum of consecutive naturals, for example, 2167 + ... + 6839.

It is an arithmetic number, because the mean of its divisors is an integer number (1869600).

Almost surely, 2^21042519 is an apocalyptic number.

21042519 is a deficient number, since it is larger than the sum of its proper divisors (8871081).

21042519 is a wasteful number, since it uses less digits than its factorization.

21042519 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4774.

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 21042519 is about 4587.2125523023. The cubic root of 21042519 is about 276.0784932177.

The spelling of 21042519 in words is "twenty-one million, forty-two thousand, five hundred nineteen".