21293761 has 2 divisors, whose sum is σ = 21293762. Its totient is φ = 21293760.

The previous prime is 21293747. The next prime is 21293777. The reversal of 21293761 is 16739212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15681600 + 5612161 = 3960^2 + 2369^2 .

It is a cyclic number.

It is not a de Polignac number, because 21293761 - 2⁷ = 21293633 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21293711) 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 as a sum of consecutive naturals, namely, 10646880 + 10646881.

It is an arithmetic number, because the mean of its divisors is an integer number (10646881).

Almost surely, 2^21293761 is an apocalyptic number.

It is an amenable number.

21293761 is a deficient number, since it is larger than the sum of its proper divisors (1).

21293761 is an equidigital number, since it uses as much as digits as its factorization.

21293761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4536, while the sum is 31.

The square root of 21293761 is about 4614.5163343518. The cubic root of 21293761 is about 277.1729165757.

The spelling of 21293761 in words is "twenty-one million, two hundred ninety-three thousand, seven hundred sixty-one".