21828507 has 4 divisors (see below), whose sum is σ = 29104680. Its totient is φ = 14552336.

The previous prime is 21828497. The next prime is 21828517. The reversal of 21828507 is 70582812.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21828497) and next prime (21828517).

It is a cyclic number.

It is not a de Polignac number, because 21828507 - 2⁴ = 21828491 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21828517) 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 3 ways as a sum of consecutive naturals, for example, 3638082 + ... + 3638087.

It is an arithmetic number, because the mean of its divisors is an integer number (7276170).

Almost surely, 2^21828507 is an apocalyptic number.

21828507 is a deficient number, since it is larger than the sum of its proper divisors (7276173).

21828507 is an equidigital number, since it uses as much as digits as its factorization.

21828507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7276172.

The product of its (nonzero) digits is 8960, while the sum is 33.

The square root of 21828507 is about 4672.0987789215. The cubic root of 21828507 is about 279.4739570569.

The spelling of 21828507 in words is "twenty-one million, eight hundred twenty-eight thousand, five hundred seven".