21147147 has 12 divisors (see below), whose sum is σ = 34909680. Its totient is φ = 12084048.

The previous prime is 21147127. The next prime is 21147157. The reversal of 21147147 is 74174112.

It is not a de Polignac number, because 21147147 - 2⁶ = 21147083 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21147147.

It is not an unprimeable number, because it can be changed into a prime (21147107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 167772 + ... + 167897.

It is an arithmetic number, because the mean of its divisors is an integer number (2909140).

Almost surely, 2^21147147 is an apocalyptic number.

21147147 is a deficient number, since it is larger than the sum of its proper divisors (13762533).

21147147 is a wasteful number, since it uses less digits than its factorization.

21147147 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 335682 (or 335679 counting only the distinct ones).

The product of its digits is 1568, while the sum is 27.

The square root of 21147147 is about 4598.6027225669. The cubic root of 21147147 is about 276.5353111067.

It can be divided in two parts, 2114 and 7147, that added together give a cube (9261 = 21³).

The spelling of 21147147 in words is "twenty-one million, one hundred forty-seven thousand, one hundred forty-seven".