21301768 has 8 divisors (see below), whose sum is σ = 39940830. Its totient is φ = 10650880.

The previous prime is 21301759. The next prime is 21301769. The reversal of 21301768 is 86710312.

It can be written as a sum of positive squares in only one way, i.e., 19554084 + 1747684 = 4422^2 + 1322^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21301769) by changing a digit.

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 as a sum of consecutive naturals, namely, 1331353 + ... + 1331368.

Almost surely, 2^21301768 is an apocalyptic number.

It is an amenable number.

21301768 is a deficient number, since it is larger than the sum of its proper divisors (18639062).

21301768 is a wasteful number, since it uses less digits than its factorization.

21301768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2662727 (or 2662723 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 21301768 is about 4615.3838410256. The cubic root of 21301768 is about 277.2076535960.

The spelling of 21301768 in words is "twenty-one million, three hundred one thousand, seven hundred sixty-eight".