21084751 has 2 divisors, whose sum is σ = 21084752. Its totient is φ = 21084750.

The previous prime is 21084733. The next prime is 21084773. The reversal of 21084751 is 15748012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21084751 - 2⁵ = 21084719 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21084451) 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 as a sum of consecutive naturals, namely, 10542375 + 10542376.

It is an arithmetic number, because the mean of its divisors is an integer number (10542376).

Almost surely, 2^21084751 is an apocalyptic number.

21084751 is a deficient number, since it is larger than the sum of its proper divisors (1).

21084751 is an equidigital number, since it uses as much as digits as its factorization.

21084751 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 21084751 is about 4591.8134761769. The cubic root of 21084751 is about 276.2630648394.

It can be divided in two parts, 2108 and 4751, that added together give a cube (6859 = 19³).

The spelling of 21084751 in words is "twenty-one million, eighty-four thousand, seven hundred fifty-one".