21384415 has 12 divisors (see below), whose sum is σ = 27788184. Its totient is φ = 15790944.

The previous prime is 21384413. The next prime is 21384421. The reversal of 21384415 is 51448312.

It is not a de Polignac number, because 21384415 - 2¹ = 21384413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21384413) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11809 + ... + 13498.

It is an arithmetic number, because the mean of its divisors is an integer number (2315682).

Almost surely, 2^21384415 is an apocalyptic number.

21384415 is a deficient number, since it is larger than the sum of its proper divisors (6403769).

21384415 is a wasteful number, since it uses less digits than its factorization.

21384415 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25338 (or 25325 counting only the distinct ones).

The product of its digits is 3840, while the sum is 28.

The square root of 21384415 is about 4624.3285999159. The cubic root of 21384415 is about 277.5656961033.

The spelling of 21384415 in words is "twenty-one million, three hundred eighty-four thousand, four hundred fifteen".