21378908 has 6 divisors (see below), whose sum is σ = 37413096. Its totient is φ = 10689452.

The previous prime is 21378899. The next prime is 21378923. The reversal of 21378908 is 80987312.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2672360 + ... + 2672367.

It is an arithmetic number, because the mean of its divisors is an integer number (6235516).

Almost surely, 2^21378908 is an apocalyptic number.

It is an amenable number.

21378908 is a deficient number, since it is larger than the sum of its proper divisors (16034188).

21378908 is a wasteful number, since it uses less digits than its factorization.

21378908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5344731 (or 5344729 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 21378908 is about 4623.7331237864. The cubic root of 21378908 is about 277.5418674486.

The spelling of 21378908 in words is "twenty-one million, three hundred seventy-eight thousand, nine hundred eight".