21847117 has 2 divisors, whose sum is σ = 21847118. Its totient is φ = 21847116.

The previous prime is 21847109. The next prime is 21847123. The reversal of 21847117 is 71174812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21846276 + 841 = 4674^2 + 29^2 .

It is a cyclic number.

It is not a de Polignac number, because 21847117 - 2³ = 21847109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21847127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10923558 + 10923559.

It is an arithmetic number, because the mean of its divisors is an integer number (10923559).

Almost surely, 2^21847117 is an apocalyptic number.

It is an amenable number.

21847117 is a deficient number, since it is larger than the sum of its proper divisors (1).

21847117 is an equidigital number, since it uses as much as digits as its factorization.

21847117 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3136, while the sum is 31.

The square root of 21847117 is about 4674.0899649023. The cubic root of 21847117 is about 279.5533567915.

The spelling of 21847117 in words is "twenty-one million, eight hundred forty-seven thousand, one hundred seventeen".