21217835707 has 2 divisors, whose sum is σ = 21217835708. Its totient is φ = 21217835706.

The previous prime is 21217835689. The next prime is 21217835713. The reversal of 21217835707 is 70753871212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21217835707 is a prime.

It is not a weakly prime, because it can be changed into another prime (21217830707) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10608917853 + 10608917854.

It is an arithmetic number, because the mean of its divisors is an integer number (10608917854).

Almost surely, 2^21217835707 is an apocalyptic number.

21217835707 is a deficient number, since it is larger than the sum of its proper divisors (1).

21217835707 is an equidigital number, since it uses as much as digits as its factorization.

21217835707 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 164640, while the sum is 43.

The spelling of 21217835707 in words is "twenty-one billion, two hundred seventeen million, eight hundred thirty-five thousand, seven hundred seven".