21201318 has 32 divisors (see below), whose sum is σ = 47416320. Its totient is φ = 7021800.

The previous prime is 21201311. The next prime is 21201347. The reversal of 21201318 is 81310212.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a self number, because there is not a number n which added to its sum of digits gives 21201318.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201311) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7843 + ... + 10193.

It is an arithmetic number, because the mean of its divisors is an integer number (1481760).

Almost surely, 2^21201318 is an apocalyptic number.

21201318 is an abundant number, since it is smaller than the sum of its proper divisors (26215002).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21201318 is a wasteful number, since it uses less digits than its factorization.

21201318 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2529 (or 2523 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 21201318 is about 4604.4888967181. The cubic root of 21201318 is about 276.7712360964.

The spelling of 21201318 in words is "twenty-one million, two hundred one thousand, three hundred eighteen".