21468678 has 64 divisors (see below), whose sum is σ = 55296000. Its totient is φ = 5392800.

The previous prime is 21468677. The next prime is 21468691. The reversal of 21468678 is 87686412.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21468677) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13573 + ... + 15071.

It is an arithmetic number, because the mean of its divisors is an integer number (864000).

Almost surely, 2^21468678 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21468678, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27648000).

21468678 is an abundant number, since it is smaller than the sum of its proper divisors (33827322).

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

21468678 is a wasteful number, since it uses less digits than its factorization.

21468678 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1553.

The product of its digits is 129024, while the sum is 42.

The square root of 21468678 is about 4633.4304785979. The cubic root of 21468678 is about 277.9297909412.

The spelling of 21468678 in words is "twenty-one million, four hundred sixty-eight thousand, six hundred seventy-eight".