21668107 has 2 divisors, whose sum is σ = 21668108. Its totient is φ = 21668106.

The previous prime is 21668099. The next prime is 21668111. The reversal of 21668107 is 70186612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21668107 - 2³ = 21668099 is a prime.

It is equal to p_1369525 and since 21668107 and 1369525 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21668137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10834053 + 10834054.

It is an arithmetic number, because the mean of its divisors is an integer number (10834054).

Almost surely, 2^21668107 is an apocalyptic number.

21668107 is a deficient number, since it is larger than the sum of its proper divisors (1).

21668107 is an equidigital number, since it uses as much as digits as its factorization.

21668107 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 21668107 is about 4654.9013953037. The cubic root of 21668107 is about 278.7877309554.

The spelling of 21668107 in words is "twenty-one million, six hundred sixty-eight thousand, one hundred seven".