21671471 has 2 divisors, whose sum is σ = 21671472. Its totient is φ = 21671470.

The previous prime is 21671431. The next prime is 21671477. The reversal of 21671471 is 17417612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21671471 - 2¹⁰ = 21670447 is a prime.

It is a super-3 number, since 3×21671471³ (a number of 23 digits) contains 333 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21671477) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10835735 + 10835736.

It is an arithmetic number, because the mean of its divisors is an integer number (10835736).

Almost surely, 2^21671471 is an apocalyptic number.

21671471 is a deficient number, since it is larger than the sum of its proper divisors (1).

21671471 is an equidigital number, since it uses as much as digits as its factorization.

21671471 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2352, while the sum is 29.

The square root of 21671471 is about 4655.2627208354. The cubic root of 21671471 is about 278.8021575871.

The spelling of 21671471 in words is "twenty-one million, six hundred seventy-one thousand, four hundred seventy-one".