21628833 has 4 divisors (see below), whose sum is σ = 28838448. Its totient is φ = 14419220.

The previous prime is 21628829. The next prime is 21628837. The reversal of 21628833 is 33882612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21628829) and next prime (21628837).

It is a cyclic number.

It is not a de Polignac number, because 21628833 - 2² = 21628829 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21628794 and 21628803.

It is not an unprimeable number, because it can be changed into a prime (21628837) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3604803 + ... + 3604808.

It is an arithmetic number, because the mean of its divisors is an integer number (7209612).

Almost surely, 2^21628833 is an apocalyptic number.

It is an amenable number.

21628833 is a deficient number, since it is larger than the sum of its proper divisors (7209615).

21628833 is an equidigital number, since it uses as much as digits as its factorization.

21628833 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7209614.

The product of its digits is 13824, while the sum is 33.

The square root of 21628833 is about 4650.6809178872. The cubic root of 21628833 is about 278.6191924486.

The spelling of 21628833 in words is "twenty-one million, six hundred twenty-eight thousand, eight hundred thirty-three".