21054851 has 2 divisors, whose sum is σ = 21054852. Its totient is φ = 21054850.

The previous prime is 21054827. The next prime is 21054863. The reversal of 21054851 is 15845012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21054851 - 2¹⁴ = 21038467 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21054851.

It is not a weakly prime, because it can be changed into another prime (21054811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10527425 + 10527426.

It is an arithmetic number, because the mean of its divisors is an integer number (10527426).

Almost surely, 2^21054851 is an apocalyptic number.

21054851 is a deficient number, since it is larger than the sum of its proper divisors (1).

21054851 is an equidigital number, since it uses as much as digits as its factorization.

21054851 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1600, while the sum is 26.

The square root of 21054851 is about 4588.5565268394. The cubic root of 21054851 is about 276.1324147579.

Adding to 21054851 its reverse (15845012), we get a palindrome (36899863).

The spelling of 21054851 in words is "twenty-one million, fifty-four thousand, eight hundred fifty-one".