21186968 has 32 divisors (see below), whose sum is σ = 43960320. Its totient is φ = 9492000.

The previous prime is 21186967. The next prime is 21186983. The reversal of 21186968 is 86968112.

It is a super-2 number, since 2×21186968² = 897775226066048, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21186967) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4553 + ... + 7943.

It is an arithmetic number, because the mean of its divisors is an integer number (1373760).

Almost surely, 2^21186968 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 21186968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21980160).

21186968 is an abundant number, since it is smaller than the sum of its proper divisors (22773352).

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

21186968 is a wasteful number, since it uses less digits than its factorization.

21186968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3479 (or 3475 counting only the distinct ones).

The product of its digits is 41472, while the sum is 41.

The square root of 21186968 is about 4602.9303709702. The cubic root of 21186968 is about 276.7087782869.

The spelling of 21186968 in words is "twenty-one million, one hundred eighty-six thousand, nine hundred sixty-eight".