21158147 has 2 divisors, whose sum is σ = 21158148. Its totient is φ = 21158146.

The previous prime is 21158141. The next prime is 21158161. The reversal of 21158147 is 74185112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21158147 - 2⁸ = 21157891 is a prime.

It is not a weakly prime, because it can be changed into another prime (21158141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10579073 + 10579074.

It is an arithmetic number, because the mean of its divisors is an integer number (10579074).

Almost surely, 2^21158147 is an apocalyptic number.

21158147 is a deficient number, since it is larger than the sum of its proper divisors (1).

21158147 is an equidigital number, since it uses as much as digits as its factorization.

21158147 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2240, while the sum is 29.

The square root of 21158147 is about 4599.7985825468. The cubic root of 21158147 is about 276.5832507673.

The spelling of 21158147 in words is "twenty-one million, one hundred fifty-eight thousand, one hundred forty-seven".