21100307 has 4 divisors (see below), whose sum is σ = 21498480. Its totient is φ = 20702136.

The previous prime is 21100297. The next prime is 21100319. The reversal of 21100307 is 70300112.

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 21100307 - 2¹⁸ = 20838163 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21100291 and 21100300.

It is not an unprimeable number, because it can be changed into a prime (21100357) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 199007 + ... + 199112.

It is an arithmetic number, because the mean of its divisors is an integer number (5374620).

Almost surely, 2^21100307 is an apocalyptic number.

21100307 is a deficient number, since it is larger than the sum of its proper divisors (398173).

21100307 is an equidigital number, since it uses as much as digits as its factorization.

21100307 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398172.

The product of its (nonzero) digits is 42, while the sum is 14.

The square root of 21100307 is about 4593.5070479972. The cubic root of 21100307 is about 276.3309889959.

Adding to 21100307 its reverse (70300112), we get a palindrome (91400419).

The spelling of 21100307 in words is "twenty-one million, one hundred thousand, three hundred seven".