21018147 has 8 divisors (see below), whose sum is σ = 28067520. Its totient is φ = 13990440.

The previous prime is 21018133. The next prime is 21018149. The reversal of 21018147 is 74181012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21018147 - 2¹⁴ = 21001763 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (21018149) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2997 + ... + 7142.

It is an arithmetic number, because the mean of its divisors is an integer number (3508440).

Almost surely, 2^21018147 is an apocalyptic number.

21018147 is a deficient number, since it is larger than the sum of its proper divisors (7049373).

21018147 is a wasteful number, since it uses less digits than its factorization.

21018147 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10833.

The product of its (nonzero) digits is 448, while the sum is 24.

The square root of 21018147 is about 4584.5552674169. Note that the first 3 decimals coincide. The cubic root of 21018147 is about 275.9718649119.

Adding to 21018147 its reverse (74181012), we get a palindrome (95199159).

The spelling of 21018147 in words is "twenty-one million, eighteen thousand, one hundred forty-seven".