21162709 has 2 divisors, whose sum is σ = 21162710. Its totient is φ = 21162708.

The previous prime is 21162697. The next prime is 21162727. The reversal of 21162709 is 90726112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19140625 + 2022084 = 4375^2 + 1422^2 .

It is a cyclic number.

It is not a de Polignac number, because 21162709 - 2¹⁹ = 20638421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21162749) 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, 10581354 + 10581355.

It is an arithmetic number, because the mean of its divisors is an integer number (10581355).

Almost surely, 2^21162709 is an apocalyptic number.

It is an amenable number.

21162709 is a deficient number, since it is larger than the sum of its proper divisors (1).

21162709 is an equidigital number, since it uses as much as digits as its factorization.

21162709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1512, while the sum is 28.

The square root of 21162709 is about 4600.2944470979. The cubic root of 21162709 is about 276.6031277775.

The spelling of 21162709 in words is "twenty-one million, one hundred sixty-two thousand, seven hundred nine".