21018514 has 16 divisors (see below), whose sum is σ = 34979040. Its totient is φ = 9391360.

The previous prime is 21018509. The next prime is 21018523. The reversal of 21018514 is 41581012.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 6799 + ... + 9394.

It is an arithmetic number, because the mean of its divisors is an integer number (2186190).

Almost surely, 2^21018514 is an apocalyptic number.

21018514 is a deficient number, since it is larger than the sum of its proper divisors (13960526).

21018514 is a wasteful number, since it uses less digits than its factorization.

21018514 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16265.

The product of its (nonzero) digits is 320, while the sum is 22.

The square root of 21018514 is about 4584.5952929348. The cubic root of 21018514 is about 275.9734711602.

Adding to 21018514 its reverse (41581012), we get a palindrome (62599526).

The spelling of 21018514 in words is "twenty-one million, eighteen thousand, five hundred fourteen".