21628826 has 8 divisors (see below), whose sum is σ = 32479380. Its totient is φ = 10802368.

The previous prime is 21628807. The next prime is 21628829. The reversal of 21628826 is 62882612.

It can be written as a sum of positive squares in 2 ways, for example, as 21613201 + 15625 = 4649^2 + 125^2 .

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

It is a super-2 number, since 2×21628826² = 935612228276552, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21628829) 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 3 ways as a sum of consecutive naturals, for example, 3581 + ... + 7488.

Almost surely, 2^21628826 is an apocalyptic number.

21628826 is a deficient number, since it is larger than the sum of its proper divisors (10850554).

21628826 is a wasteful number, since it uses less digits than its factorization.

21628826 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12048.

The product of its digits is 18432, while the sum is 35.

The square root of 21628826 is about 4650.6801653092. The cubic root of 21628826 is about 278.6191623910.

The spelling of 21628826 in words is "twenty-one million, six hundred twenty-eight thousand, eight hundred twenty-six".