21247069 has 2 divisors, whose sum is σ = 21247070. Its totient is φ = 21247068.

The previous prime is 21247063. The next prime is 21247081. The reversal of 21247069 is 96074212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14538969 + 6708100 = 3813^2 + 2590^2 .

It is a cyclic number.

It is not a de Polignac number, because 21247069 - 2⁹ = 21246557 is a prime.

It is a super-2 number, since 2×21247069² = 902875882181522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21247069.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21247063) 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, 10623534 + 10623535.

It is an arithmetic number, because the mean of its divisors is an integer number (10623535).

Almost surely, 2^21247069 is an apocalyptic number.

It is an amenable number.

21247069 is a deficient number, since it is larger than the sum of its proper divisors (1).

21247069 is an equidigital number, since it uses as much as digits as its factorization.

21247069 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 21247069 is about 4609.4543060974. The cubic root of 21247069 is about 276.9701775554.

The spelling of 21247069 in words is "twenty-one million, two hundred forty-seven thousand, sixty-nine".