21111073 has 2 divisors, whose sum is σ = 21111074. Its totient is φ = 21111072.

The previous prime is 21111061. The next prime is 21111113. The reversal of 21111073 is 37011112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16916769 + 4194304 = 4113^2 + 2048^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21111073 is a prime.

It is a super-2 number, since 2×21111073² = 891354806422658, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21111173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555536 + 10555537.

It is an arithmetic number, because the mean of its divisors is an integer number (10555537).

Almost surely, 2^21111073 is an apocalyptic number.

It is an amenable number.

21111073 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111073 is an equidigital number, since it uses as much as digits as its factorization.

21111073 is an odious number, because the sum of its binary digits is odd.

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

The square root of 21111073 is about 4594.6787700556. The cubic root of 21111073 is about 276.3779784165.

Adding to 21111073 its reverse (37011112), we get a palindrome (58122185).

The spelling of 21111073 in words is "twenty-one million, one hundred eleven thousand, seventy-three".