21392316 has 72 divisors (see below), whose sum is σ = 60999120. Its totient is φ = 6478560.

The previous prime is 21392303. The next prime is 21392317. The reversal of 21392316 is 61329312.

It is a Harshad number since it is a multiple of its sum of digits (27).

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

It is a plaindrome in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 21392316.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21392317) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12250 + ... + 13886.

It is an arithmetic number, because the mean of its divisors is an integer number (847210).

Almost surely, 2^21392316 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21392316, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30499560).

21392316 is an abundant number, since it is smaller than the sum of its proper divisors (39606804).

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

21392316 is a wasteful number, since it uses less digits than its factorization.

21392316 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1672 (or 1653 counting only the distinct ones).

The product of its digits is 1944, while the sum is 27.

The square root of 21392316 is about 4625.1828071980. The cubic root of 21392316 is about 277.5998763935.

It can be divided in two parts, 213 and 92316, that added together give a palindrome (92529).

The spelling of 21392316 in words is "twenty-one million, three hundred ninety-two thousand, three hundred sixteen".