21046147 has 2 divisors, whose sum is σ = 21046148. Its totient is φ = 21046146.

The previous prime is 21046139. The next prime is 21046169. The reversal of 21046147 is 74164012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21046147 - 2³ = 21046139 is a prime.

It is not a weakly prime, because it can be changed into another prime (21046447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10523073 + 10523074.

It is an arithmetic number, because the mean of its divisors is an integer number (10523074).

Almost surely, 2^21046147 is an apocalyptic number.

21046147 is a deficient number, since it is larger than the sum of its proper divisors (1).

21046147 is an equidigital number, since it uses as much as digits as its factorization.

21046147 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 21046147 is about 4587.6079823804. The cubic root of 21046147 is about 276.0943587963.

The spelling of 21046147 in words is "twenty-one million, forty-six thousand, one hundred forty-seven".