21369726 has 48 divisors (see below), whose sum is σ = 54632448. Its totient is φ = 5907600.

The previous prime is 21369713. The next prime is 21369739. The reversal of 21369726 is 62796312.

It is an interprime number because it is at equal distance from previous prime (21369713) and next prime (21369739).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a nude number because it is divisible by every one of its digits.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1171 + ... + 6641.

It is an arithmetic number, because the mean of its divisors is an integer number (1138176).

Almost surely, 2^21369726 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21369726, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27316224).

21369726 is an abundant number, since it is smaller than the sum of its proper divisors (33262722).

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

21369726 is a wasteful number, since it uses less digits than its factorization.

21369726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5517 (or 5514 counting only the distinct ones).

The product of its digits is 27216, while the sum is 36.

The square root of 21369726 is about 4622.7400965228. The cubic root of 21369726 is about 277.5021280577.

The spelling of 21369726 in words is "twenty-one million, three hundred sixty-nine thousand, seven hundred twenty-six".