21053768 has 16 divisors (see below), whose sum is σ = 40837500. Its totient is φ = 10163776.

The previous prime is 21053741. The next prime is 21053783. The reversal of 21053768 is 86735012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 20448484 + 605284 = 4522^2 + 778^2 .

It is a super-2 number, since 2×21053768² = 886522293995648, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45143 + ... + 45606.

Almost surely, 2^21053768 is an apocalyptic number.

It is an amenable number.

21053768 is a deficient number, since it is larger than the sum of its proper divisors (19783732).

21053768 is a wasteful number, since it uses less digits than its factorization.

21053768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90784 (or 90780 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 21053768 is about 4588.4385143532. The cubic root of 21053768 is about 276.1276801953.

The spelling of 21053768 in words is "twenty-one million, fifty-three thousand, seven hundred sixty-eight".