21847867 has 2 divisors, whose sum is σ = 21847868. Its totient is φ = 21847866.

The previous prime is 21847831. The next prime is 21847879. The reversal of 21847867 is 76874812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21847867 - 2¹⁵ = 21815099 is a prime.

It is not a weakly prime, because it can be changed into another prime (21842867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10923933 + 10923934.

It is an arithmetic number, because the mean of its divisors is an integer number (10923934).

Almost surely, 2^21847867 is an apocalyptic number.

21847867 is a deficient number, since it is larger than the sum of its proper divisors (1).

21847867 is an equidigital number, since it uses as much as digits as its factorization.

21847867 is an evil number, because the sum of its binary digits is even.

The product of its digits is 150528, while the sum is 43.

The square root of 21847867 is about 4674.1701937349. The cubic root of 21847867 is about 279.5565557280.

The spelling of 21847867 in words is "twenty-one million, eight hundred forty-seven thousand, eight hundred sixty-seven".