21278748 has 12 divisors (see below), whose sum is σ = 49650440. Its totient is φ = 7092912.

The previous prime is 21278711. The next prime is 21278773. The reversal of 21278748 is 84787212.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

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, 886603 + ... + 886626.

Almost surely, 2^21278748 is an apocalyptic number.

It is an amenable number.

21278748 is an abundant number, since it is smaller than the sum of its proper divisors (28371692).

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

21278748 is a wasteful number, since it uses less digits than its factorization.

21278748 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1773236 (or 1773234 counting only the distinct ones).

The product of its digits is 50176, while the sum is 39.

The square root of 21278748 is about 4612.8893331620. The cubic root of 21278748 is about 277.1077617271.

The spelling of 21278748 in words is "twenty-one million, two hundred seventy-eight thousand, seven hundred forty-eight".