21318726 has 32 divisors (see below), whose sum is σ = 50093568. Its totient is φ = 5963040.

The previous prime is 21318709. The next prime is 21318727. The reversal of 21318726 is 62781312.

It is a junction number, because it is equal to n+sod(n) for n = 21318693 and 21318702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21318727) 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, 11566 + ... + 13281.

It is an arithmetic number, because the mean of its divisors is an integer number (1565424).

Almost surely, 2^21318726 is an apocalyptic number.

21318726 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21318726 is an abundant number, since it is smaller than the sum of its proper divisors (28774842).

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

21318726 is a wasteful number, since it uses less digits than its factorization.

21318726 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24876.

The product of its digits is 4032, while the sum is 30.

The square root of 21318726 is about 4617.2205925210. The cubic root of 21318726 is about 277.2811942916.

The spelling of 21318726 in words is "twenty-one million, three hundred eighteen thousand, seven hundred twenty-six".