21711147 has 8 divisors (see below), whose sum is σ = 28976640. Its totient is φ = 14459880.

The previous prime is 21711143. The next prime is 21711163. The reversal of 21711147 is 74111712.

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

It is not a de Polignac number, because 21711147 - 2² = 21711143 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21711143) 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, 754 + ... + 6632.

It is an arithmetic number, because the mean of its divisors is an integer number (3622080).

Almost surely, 2^21711147 is an apocalyptic number.

21711147 is a deficient number, since it is larger than the sum of its proper divisors (7265493).

21711147 is a wasteful number, since it uses less digits than its factorization.

21711147 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7113.

The product of its digits is 392, while the sum is 24.

The square root of 21711147 is about 4659.5221858040. The cubic root of 21711147 is about 278.9721969699.

Subtracting from 21711147 its product of digits (392), we obtain a triangular number (21710755 = T₆₅₈₉).

Adding to 21711147 its reverse (74111712), we get a palindrome (95822859).

The spelling of 21711147 in words is "twenty-one million, seven hundred eleven thousand, one hundred forty-seven".