21031768 has 32 divisors (see below), whose sum is σ = 40392000. Its totient is φ = 10264320.

The previous prime is 21031753. The next prime is 21031781. The reversal of 21031768 is 86713012.

It is a congruent 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 7 ways as a sum of consecutive naturals, for example, 77473 + ... + 77743.

It is an arithmetic number, because the mean of its divisors is an integer number (1262250).

Almost surely, 2^21031768 is an apocalyptic number.

It is an amenable number.

21031768 is a deficient number, since it is larger than the sum of its proper divisors (19360232).

21031768 is a wasteful number, since it uses less digits than its factorization.

21031768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 475 (or 471 counting only the distinct ones).

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

The square root of 21031768 is about 4586.0405580413. The cubic root of 21031768 is about 276.0314673917.

The spelling of 21031768 in words is "twenty-one million, thirty-one thousand, seven hundred sixty-eight".