21111005 has 8 divisors (see below), whose sum is σ = 25495512. Its totient is φ = 16780608.

The previous prime is 21110989. The next prime is 21111007. The reversal of 21111005 is 50011112.

It can be written as a sum of positive squares in 4 ways, for example, as 4813636 + 16297369 = 2194^2 + 4037^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21111005 - 2⁴ = 21110989 is a prime.

It is a super-2 number, since 2×21111005² = 891349064220050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111007) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12662 + ... + 14231.

It is an arithmetic number, because the mean of its divisors is an integer number (3186939).

Almost surely, 2^21111005 is an apocalyptic number.

It is an amenable number.

21111005 is a deficient number, since it is larger than the sum of its proper divisors (4384507).

21111005 is a wasteful number, since it uses less digits than its factorization.

21111005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27055.

The product of its (nonzero) digits is 10, while the sum is 11.

The square root of 21111005 is about 4594.6713701852. The cubic root of 21111005 is about 276.3776816729.

Adding to 21111005 its reverse (50011112), we get a palindrome (71122117).

The spelling of 21111005 in words is "twenty-one million, one hundred eleven thousand, five".