21111307 has 16 divisors (see below), whose sum is σ = 25048000. Its totient is φ = 17781120.

The previous prime is 21111301. The next prime is 21111373. The reversal of 21111307 is 70311112.

It is not a de Polignac number, because 21111307 - 2⁷ = 21111179 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21111301) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20419 + ... + 21427.

It is an arithmetic number, because the mean of its divisors is an integer number (1565500).

Almost surely, 2^21111307 is an apocalyptic number.

21111307 is a deficient number, since it is larger than the sum of its proper divisors (3936693).

21111307 is an equidigital number, since it uses as much as digits as its factorization.

21111307 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1091 (or 1077 counting only the distinct ones).

The product of its (nonzero) digits is 42, while the sum is 16.

The square root of 21111307 is about 4594.7042342244. The cubic root of 21111307 is about 276.3789995584.

Adding to 21111307 its reverse (70311112), we get a palindrome (91422419).

The spelling of 21111307 in words is "twenty-one million, one hundred eleven thousand, three hundred seven".