21660107 has 8 divisors (see below), whose sum is σ = 25260000. Its totient is φ = 18565512.

The previous prime is 21660101. The next prime is 21660109. The reversal of 21660107 is 70106612.

It is not a de Polignac number, because 21660107 - 2⁸ = 21659851 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21660101) 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 7 ways as a sum of consecutive naturals, for example, 31232 + ... + 31917.

It is an arithmetic number, because the mean of its divisors is an integer number (3157500).

Almost surely, 2^21660107 is an apocalyptic number.

21660107 is a deficient number, since it is larger than the sum of its proper divisors (3599893).

21660107 is an frugal number, since it uses more digits than its factorization.

21660107 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63170 (or 63156 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 21660107 is about 4654.0420066862. The cubic root of 21660107 is about 278.7534166767.

Adding to 21660107 its reverse (70106612), we get a palindrome (91766719).

The spelling of 21660107 in words is "twenty-one million, six hundred sixty thousand, one hundred seven".