21008247707 has 2 divisors, whose sum is σ = 21008247708. Its totient is φ = 21008247706.

The previous prime is 21008247691. The next prime is 21008247713. The reversal of 21008247707 is 70774280012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21008247707 - 2⁴ = 21008247691 is a prime.

It is not a weakly prime, because it can be changed into another prime (21008247737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10504123853 + 10504123854.

It is an arithmetic number, because the mean of its divisors is an integer number (10504123854).

Almost surely, 2^21008247707 is an apocalyptic number.

21008247707 is a deficient number, since it is larger than the sum of its proper divisors (1).

21008247707 is an equidigital number, since it uses as much as digits as its factorization.

21008247707 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 43904, while the sum is 38.

The spelling of 21008247707 in words is "twenty-one billion, eight million, two hundred forty-seven thousand, seven hundred seven".