21628413 has 12 divisors (see below), whose sum is σ = 31906368. Its totient is φ = 14111880.

The previous prime is 21628379. The next prime is 21628417. The reversal of 21628413 is 31482612.

21628413 is a `hidden beast` number, since 21 + 628 + 4 + 13 = 666.

It is not a de Polignac number, because 21628413 - 2⁹ = 21627901 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21628417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25143 + ... + 25988.

It is an arithmetic number, because the mean of its divisors is an integer number (2658864).

Almost surely, 2^21628413 is an apocalyptic number.

It is an amenable number.

21628413 is a deficient number, since it is larger than the sum of its proper divisors (10277955).

21628413 is a wasteful number, since it uses less digits than its factorization.

21628413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51184 (or 51181 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 21628413 is about 4650.6357629898. The cubic root of 21628413 is about 278.6173889792.

The spelling of 21628413 in words is "twenty-one million, six hundred twenty-eight thousand, four hundred thirteen".