21414728 has 16 divisors (see below), whose sum is σ = 40213500. Its totient is φ = 10691136.

The previous prime is 21414719. The next prime is 21414733. The reversal of 21414728 is 82741412.

It can be written as a sum of positive squares in 2 ways, for example, as 21325924 + 88804 = 4618^2 + 298^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21414728.

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, 5018 + ... + 8246.

Almost surely, 2^21414728 is an apocalyptic number.

It is an amenable number.

21414728 is a deficient number, since it is larger than the sum of its proper divisors (18798772).

21414728 is a wasteful number, since it uses less digits than its factorization.

21414728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4064 (or 4060 counting only the distinct ones).

The product of its digits is 3584, while the sum is 29.

The square root of 21414728 is about 4627.6049961076. The cubic root of 21414728 is about 277.6967865330.

The spelling of 21414728 in words is "twenty-one million, four hundred fourteen thousand, seven hundred twenty-eight".