21668124091 has 2 divisors, whose sum is σ = 21668124092. Its totient is φ = 21668124090.

The previous prime is 21668124067. The next prime is 21668124113. The reversal of 21668124091 is 19042186612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21668124091 - 2⁵ = 21668124059 is a prime.

It is not a weakly prime, because it can be changed into another prime (21668124011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10834062045 + 10834062046.

It is an arithmetic number, because the mean of its divisors is an integer number (10834062046).

Almost surely, 2^21668124091 is an apocalyptic number.

21668124091 is a deficient number, since it is larger than the sum of its proper divisors (1).

21668124091 is an equidigital number, since it uses as much as digits as its factorization.

21668124091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 41472, while the sum is 40.

The spelling of 21668124091 in words is "twenty-one billion, six hundred sixty-eight million, one hundred twenty-four thousand, ninety-one".