21047159 has 4 divisors (see below), whose sum is σ = 24053904. Its totient is φ = 18040416.

The previous prime is 21047153. The next prime is 21047183. The reversal of 21047159 is 95174012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21047159 - 2⁸ = 21046903 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21047153) 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 in 3 ways as a sum of consecutive naturals, for example, 1503362 + ... + 1503375.

It is an arithmetic number, because the mean of its divisors is an integer number (6013476).

Almost surely, 2^21047159 is an apocalyptic number.

21047159 is a deficient number, since it is larger than the sum of its proper divisors (3006745).

21047159 is an equidigital number, since it uses as much as digits as its factorization.

21047159 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3006744.

The product of its (nonzero) digits is 2520, while the sum is 29.

The square root of 21047159 is about 4587.7182781858. The cubic root of 21047159 is about 276.0987840404.

The spelling of 21047159 in words is "twenty-one million, forty-seven thousand, one hundred fifty-nine".