21671347 has 2 divisors, whose sum is σ = 21671348. Its totient is φ = 21671346.

The previous prime is 21671341. The next prime is 21671357. The reversal of 21671347 is 74317612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21671347 - 2¹¹ = 21669299 is a prime.

It is equal to p_1369723 and since 21671347 and 1369723 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21671341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10835673 + 10835674.

It is an arithmetic number, because the mean of its divisors is an integer number (10835674).

Almost surely, 2^21671347 is an apocalyptic number.

21671347 is a deficient number, since it is larger than the sum of its proper divisors (1).

21671347 is an equidigital number, since it uses as much as digits as its factorization.

21671347 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7056, while the sum is 31.

The square root of 21671347 is about 4655.2494025562. The cubic root of 21671347 is about 278.8016258352.

Adding to 21671347 its reverse (74317612), we get a palindrome (95988959).

The spelling of 21671347 in words is "twenty-one million, six hundred seventy-one thousand, three hundred forty-seven".