21663107 has 4 divisors (see below), whose sum is σ = 21886536. Its totient is φ = 21439680.

The previous prime is 21663101. The next prime is 21663119. The reversal of 21663107 is 70136612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21663107 - 2⁴ = 21663091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21663101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 111569 + ... + 111762.

It is an arithmetic number, because the mean of its divisors is an integer number (5471634).

Almost surely, 2^21663107 is an apocalyptic number.

21663107 is a deficient number, since it is larger than the sum of its proper divisors (223429).

21663107 is an equidigital number, since it uses as much as digits as its factorization.

21663107 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223428.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 21663107 is about 4654.3642960129. The cubic root of 21663107 is about 278.7662855212.

Adding to 21663107 its reverse (70136612), we get a palindrome (91799719).

The spelling of 21663107 in words is "twenty-one million, six hundred sixty-three thousand, one hundred seven".