21197316 has 48 divisors (see below), whose sum is σ = 56999936. Its totient is φ = 6005664.

The previous prime is 21197311. The next prime is 21197321. The reversal of 21197316 is 61379112.

It is an interprime number because it is at equal distance from previous prime (21197311) and next prime (21197321).

It is not an unprimeable number, because it can be changed into a prime (21197311) 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, 9675 + ... + 11661.

Almost surely, 2^21197316 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 21197316, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28499968).

21197316 is an abundant number, since it is smaller than the sum of its proper divisors (35802620).

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

21197316 is a wasteful number, since it uses less digits than its factorization.

21197316 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2128 (or 2126 counting only the distinct ones).

The product of its digits is 2268, while the sum is 30.

The square root of 21197316 is about 4604.0543002880. The cubic root of 21197316 is about 276.7538203837.

The spelling of 21197316 in words is "twenty-one million, one hundred ninety-seven thousand, three hundred sixteen".