21986316 has 120 divisors (see below), whose sum is σ = 65049600. Its totient is φ = 6415200.

The previous prime is 21986309. The next prime is 21986317. The reversal of 21986316 is 61368912.

21986316 is a `hidden beast` number, since 2 + 19 + 8 + 631 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21986317) by changing a digit.

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 39 ways as a sum of consecutive naturals, for example, 110385 + ... + 110583.

It is an arithmetic number, because the mean of its divisors is an integer number (542080).

Almost surely, 2^21986316 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 21986316, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32524800).

21986316 is an abundant number, since it is smaller than the sum of its proper divisors (43063284).

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

21986316 is a wasteful number, since it uses less digits than its factorization.

21986316 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257 (or 246 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 21986316 is about 4688.9568136207. The cubic root of 21986316 is about 280.1458254008.

The spelling of 21986316 in words is "twenty-one million, nine hundred eighty-six thousand, three hundred sixteen".