21001318 has 16 divisors (see below), whose sum is σ = 34246800. Its totient is φ = 9601056.

The previous prime is 21001247. The next prime is 21001319. The reversal of 21001318 is 81310012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001319) 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, 993 + ... + 6556.

It is an arithmetic number, because the mean of its divisors is an integer number (2140425).

Almost surely, 2^21001318 is an apocalyptic number.

21001318 is a deficient number, since it is larger than the sum of its proper divisors (13245482).

21001318 is a wasteful number, since it uses less digits than its factorization.

21001318 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7671.

The product of its (nonzero) digits is 48, while the sum is 16.

The square root of 21001318 is about 4582.7194982892. The cubic root of 21001318 is about 275.8981893619.

The spelling of 21001318 in words is "twenty-one million, one thousand, three hundred eighteen".