21378268 has 24 divisors (see below), whose sum is σ = 39777920. Its totient is φ = 10024560.

The previous prime is 21378233. The next prime is 21378271. The reversal of 21378268 is 86287312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6463 + ... + 9193.

Almost surely, 2^21378268 is an apocalyptic number.

It is an amenable number.

21378268 is a deficient number, since it is larger than the sum of its proper divisors (18399652).

21378268 is a wasteful number, since it uses less digits than its factorization.

21378268 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2857 (or 2855 counting only the distinct ones).

The product of its digits is 32256, while the sum is 37.

The square root of 21378268 is about 4623.6639151219. The cubic root of 21378268 is about 277.5390979189.

The spelling of 21378268 in words is "twenty-one million, three hundred seventy-eight thousand, two hundred sixty-eight".