21201111111689 has 2 divisors, whose sum is σ = 21201111111690. Its totient is φ = 21201111111688.

The previous prime is 21201111111683. The next prime is 21201111111707. The reversal of 21201111111689 is 98611111110212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20201501073664 + 999610038025 = 4494608^2 + 999805^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201111111689 - 2⁴ = 21201111111673 is a prime.

It is a super-2 number, since 2×21201111111689² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21201111111683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600555555844 + 10600555555845.

It is an arithmetic number, because the mean of its divisors is an integer number (10600555555845).

Almost surely, 2^{21201111111689} is an apocalyptic number.

It is an amenable number.

21201111111689 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201111111689 is an equidigital number, since it uses as much as digits as its factorization.

21201111111689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 35.

The spelling of 21201111111689 in words is "twenty-one trillion, two hundred one billion, one hundred eleven million, one hundred eleven thousand, six hundred eighty-nine".