21986712 has 192 divisors, whose sum is σ = 72783360. Its totient is φ = 5913600.

The previous prime is 21986711. The next prime is 21986737. The reversal of 21986712 is 21768912.

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 (21986711) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 309637 + ... + 309707.

It is an arithmetic number, because the mean of its divisors is an integer number (379080).

Almost surely, 2^21986712 is an apocalyptic number.

21986712 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21986712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36391680).

21986712 is an abundant number, since it is smaller than the sum of its proper divisors (50796648).

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

21986712 is a wasteful number, since it uses less digits than its factorization.

21986712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134 (or 127 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 21986712 is about 4688.9990403070. Note that the first 3 decimals coincide. The cubic root of 21986712 is about 280.1475073118.

The spelling of 21986712 in words is "twenty-one million, nine hundred eighty-six thousand, seven hundred twelve".