21147111 has 6 divisors (see below), whose sum is σ = 30545840. Its totient is φ = 14098068.

The previous prime is 21147107. The next prime is 21147127. The reversal of 21147111 is 11174112.

It is not a de Polignac number, because 21147111 - 2² = 21147107 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21147211) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1174831 + ... + 1174848.

Almost surely, 2^21147111 is an apocalyptic number.

21147111 is a deficient number, since it is larger than the sum of its proper divisors (9398729).

21147111 is a wasteful number, since it uses less digits than its factorization.

21147111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2349685 (or 2349682 counting only the distinct ones).

The product of its digits is 56, while the sum is 18.

The square root of 21147111 is about 4598.5988083328. The cubic root of 21147111 is about 276.5351541860.

The spelling of 21147111 in words is "twenty-one million, one hundred forty-seven thousand, one hundred eleven".