21351248 has 10 divisors (see below), whose sum is σ = 41368074. Its totient is φ = 10675616.

The previous prime is 21351241. The next prime is 21351287. The reversal of 21351248 is 84215312.

It can be written as a sum of positive squares in only one way, i.e., 19254544 + 2096704 = 4388^2 + 1448^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21351241) by changing a digit.

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 as a sum of consecutive naturals, namely, 667211 + ... + 667242.

Almost surely, 2^21351248 is an apocalyptic number.

It is an amenable number.

21351248 is a deficient number, since it is larger than the sum of its proper divisors (20016826).

21351248 is a wasteful number, since it uses less digits than its factorization.

21351248 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1334461 (or 1334455 counting only the distinct ones).

The product of its digits is 1920, while the sum is 26.

The square root of 21351248 is about 4620.7410661062. The cubic root of 21351248 is about 277.4221213702.

The spelling of 21351248 in words is "twenty-one million, three hundred fifty-one thousand, two hundred forty-eight".