21078884 has 12 divisors (see below), whose sum is σ = 38078208. Its totient is φ = 10199400.

The previous prime is 21078877. The next prime is 21078919. The reversal of 21078884 is 48887012.

It is a happy number.

It is a super-3 number, since 3×21078884³ (a number of 23 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 84872 + ... + 85119.

It is an arithmetic number, because the mean of its divisors is an integer number (3173184).

Almost surely, 2^21078884 is an apocalyptic number.

It is an amenable number.

21078884 is a deficient number, since it is larger than the sum of its proper divisors (16999324).

21078884 is a wasteful number, since it uses less digits than its factorization.

21078884 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170026 (or 170024 counting only the distinct ones).

The product of its (nonzero) digits is 28672, while the sum is 38.

The square root of 21078884 is about 4591.1745773821. The cubic root of 21078884 is about 276.2374383292.

The spelling of 21078884 in words is "twenty-one million, seventy-eight thousand, eight hundred eighty-four".