21138248 has 16 divisors (see below), whose sum is σ = 40705980. Its totient is φ = 10283328.

The previous prime is 21138239. The next prime is 21138251. The reversal of 21138248 is 84283112.

It can be written as a sum of positive squares in 2 ways, for example, as 20052484 + 1085764 = 4478^2 + 1042^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21138248.

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, 35411 + ... + 36002.

Almost surely, 2^21138248 is an apocalyptic number.

It is an amenable number.

21138248 is a deficient number, since it is larger than the sum of its proper divisors (19567732).

21138248 is a wasteful number, since it uses less digits than its factorization.

21138248 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71456 (or 71452 counting only the distinct ones).

The product of its digits is 3072, while the sum is 29.

The square root of 21138248 is about 4597.6350442374. The cubic root of 21138248 is about 276.4965157552.

The spelling of 21138248 in words is "twenty-one million, one hundred thirty-eight thousand, two hundred forty-eight".