21015449 has 8 divisors (see below), whose sum is σ = 25865280. Its totient is φ = 16627536.

The previous prime is 21015437. The next prime is 21015461. The reversal of 21015449 is 94451012.

It is an interprime number because it is at equal distance from previous prime (21015437) and next prime (21015461).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21015449 - 2²⁰ = 19966873 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21015409) 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 7 ways as a sum of consecutive naturals, for example, 115379 + ... + 115560.

It is an arithmetic number, because the mean of its divisors is an integer number (3233160).

Almost surely, 2^21015449 is an apocalyptic number.

It is an amenable number.

21015449 is a deficient number, since it is larger than the sum of its proper divisors (4849831).

21015449 is a wasteful number, since it uses less digits than its factorization.

21015449 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230959.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 21015449 is about 4584.2610091486. The cubic root of 21015449 is about 275.9600560061.

The spelling of 21015449 in words is "twenty-one million, fifteen thousand, four hundred forty-nine".