21104851 has 2 divisors, whose sum is σ = 21104852. Its totient is φ = 21104850.

The previous prime is 21104849. The next prime is 21104857. The reversal of 21104851 is 15840112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21104851 - 2¹ = 21104849 is a prime.

Together with 21104849, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21104857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10552425 + 10552426.

It is an arithmetic number, because the mean of its divisors is an integer number (10552426).

Almost surely, 2^21104851 is an apocalyptic number.

21104851 is the 2055-th centered decagonal number.

21104851 is a deficient number, since it is larger than the sum of its proper divisors (1).

21104851 is an equidigital number, since it uses as much as digits as its factorization.

21104851 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 320, while the sum is 22.

The square root of 21104851 is about 4594.0016325639. The cubic root of 21104851 is about 276.3508237451.

Adding to 21104851 its reverse (15840112), we get a palindrome (36944963).

The spelling of 21104851 in words is "twenty-one million, one hundred four thousand, eight hundred fifty-one".