21610666111 has 2 divisors, whose sum is σ = 21610666112. Its totient is φ = 21610666110.

The previous prime is 21610666087. The next prime is 21610666123. The reversal of 21610666111 is 11166601612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21610666111 - 2¹¹ = 21610664063 is a prime.

It is a super-2 number, since 2×21610666111² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21610666141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10805333055 + 10805333056.

It is an arithmetic number, because the mean of its divisors is an integer number (10805333056).

Almost surely, 2^21610666111 is an apocalyptic number.

21610666111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21610666111 is an equidigital number, since it uses as much as digits as its factorization.

21610666111 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 31.

The spelling of 21610666111 in words is "twenty-one billion, six hundred ten million, six hundred sixty-six thousand, one hundred eleven".