21418776 has 128 divisors (see below), whose sum is σ = 66528000. Its totient is φ = 6345216.

The previous prime is 21418763. The next prime is 21418777. The reversal of 21418776 is 67781412.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21418776.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21418777) 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, 69615 + ... + 69921.

It is an arithmetic number, because the mean of its divisors is an integer number (519750).

Almost surely, 2^21418776 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 21418776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33264000).

21418776 is an abundant number, since it is smaller than the sum of its proper divisors (45109224).

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

21418776 is a wasteful number, since it uses less digits than its factorization.

21418776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 358 (or 348 counting only the distinct ones).

The product of its digits is 18816, while the sum is 36.

The square root of 21418776 is about 4628.0423507137. The cubic root of 21418776 is about 277.7142829926.

The spelling of 21418776 in words is "twenty-one million, four hundred eighteen thousand, seven hundred seventy-six".