21111945667 has 2 divisors, whose sum is σ = 21111945668. Its totient is φ = 21111945666.

The previous prime is 21111945661. The next prime is 21111945691. The reversal of 21111945667 is 76654911112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21111945667 - 2⁷ = 21111945539 is a prime.

It is not a weakly prime, because it can be changed into another prime (21111945661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555972833 + 10555972834.

It is an arithmetic number, because the mean of its divisors is an integer number (10555972834).

Almost surely, 2^21111945667 is an apocalyptic number.

21111945667 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111945667 is an equidigital number, since it uses as much as digits as its factorization.

21111945667 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90720, while the sum is 43.

The spelling of 21111945667 in words is "twenty-one billion, one hundred eleven million, nine hundred forty-five thousand, six hundred sixty-seven".