21006318 has 16 divisors (see below), whose sum is σ = 42296400. Its totient is φ = 6954816.

The previous prime is 21006311. The next prime is 21006329. The reversal of 21006318 is 81360012.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21006294 and 21006303.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21006311) 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, 10855 + ... + 12642.

It is an arithmetic number, because the mean of its divisors is an integer number (2643525).

Almost surely, 2^21006318 is an apocalyptic number.

21006318 is an abundant number, since it is smaller than the sum of its proper divisors (21290082).

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

21006318 is a wasteful number, since it uses less digits than its factorization.

21006318 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23651.

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 21006318 is about 4583.2649934299. The cubic root of 21006318 is about 275.9200829320.

The spelling of 21006318 in words is "twenty-one million, six thousand, three hundred eighteen".