21378884 has 12 divisors (see below), whose sum is σ = 37448208. Its totient is φ = 10679400.

The previous prime is 21378883. The next prime is 21378899. The reversal of 21378884 is 48887312.

It is a super-3 number, since 3×21378884³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21378883) 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 3 ways as a sum of consecutive naturals, for example, 4379 + ... + 7869.

It is an arithmetic number, because the mean of its divisors is an integer number (3120684).

Almost surely, 2^21378884 is an apocalyptic number.

It is an amenable number.

21378884 is a deficient number, since it is larger than the sum of its proper divisors (16069324).

21378884 is a wasteful number, since it uses less digits than its factorization.

21378884 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5026 (or 5024 counting only the distinct ones).

The product of its digits is 86016, while the sum is 41.

The square root of 21378884 is about 4623.7305284802. The cubic root of 21378884 is about 277.5417635923.

It can be divided in two parts, 213 and 78884, that added together give a palindrome (79097).

The spelling of 21378884 in words is "twenty-one million, three hundred seventy-eight thousand, eight hundred eighty-four".