21248618 has 8 divisors (see below), whose sum is σ = 32395620. Its totient is φ = 10450080.

The previous prime is 21248599. The next prime is 21248639. The reversal of 21248618 is 81684212.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 21187609 + 61009 = 4603^2 + 247^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86963 + ... + 87206.

Almost surely, 2^21248618 is an apocalyptic number.

21248618 is a deficient number, since it is larger than the sum of its proper divisors (11147002).

21248618 is a wasteful number, since it uses less digits than its factorization.

21248618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174232.

The product of its digits is 6144, while the sum is 32.

The square root of 21248618 is about 4609.6223272628. The cubic root of 21248618 is about 276.9769081525.

The spelling of 21248618 in words is "twenty-one million, two hundred forty-eight thousand, six hundred eighteen".