21750481 has 2 divisors, whose sum is σ = 21750482. Its totient is φ = 21750480.

The previous prime is 21750467. The next prime is 21750503. The reversal of 21750481 is 18405712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21538881 + 211600 = 4641^2 + 460^2 .

It is a cyclic number.

It is not a de Polignac number, because 21750481 - 2¹⁹ = 21226193 is a prime.

It is a super-2 number, since 2×21750481² = 946166847462722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21750461) 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, 10875240 + 10875241.

It is an arithmetic number, because the mean of its divisors is an integer number (10875241).

Almost surely, 2^21750481 is an apocalyptic number.

It is an amenable number.

21750481 is a deficient number, since it is larger than the sum of its proper divisors (1).

21750481 is an equidigital number, since it uses as much as digits as its factorization.

21750481 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 21750481 is about 4663.7410948722. The cubic root of 21750481 is about 279.1405662784.

The spelling of 21750481 in words is "twenty-one million, seven hundred fifty thousand, four hundred eighty-one".