21166311707 has 2 divisors, whose sum is σ = 21166311708. Its totient is φ = 21166311706.

The previous prime is 21166311659. The next prime is 21166311739. The reversal of 21166311707 is 70711366112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21166311707 - 2⁶ = 21166311643 is a prime.

It is not a weakly prime, because it can be changed into another prime (21166311007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10583155853 + 10583155854.

It is an arithmetic number, because the mean of its divisors is an integer number (10583155854).

Almost surely, 2^21166311707 is an apocalyptic number.

21166311707 is a deficient number, since it is larger than the sum of its proper divisors (1).

21166311707 is an equidigital number, since it uses as much as digits as its factorization.

21166311707 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10584, while the sum is 35.

Adding to 21166311707 its reverse (70711366112), we get a palindrome (91877677819).

The spelling of 21166311707 in words is "twenty-one billion, one hundred sixty-six million, three hundred eleven thousand, seven hundred seven".