21858768 has 40 divisors (see below), whose sum is σ = 62744000. Its totient is φ = 7286112.

The previous prime is 21858743. The next prime is 21858769. The reversal of 21858768 is 86785812.

21858768 is a `hidden beast` number, since 2 + 1 + 8 + 587 + 68 = 666.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21858769) 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 in 7 ways as a sum of consecutive naturals, for example, 24868 + ... + 25731.

It is an arithmetic number, because the mean of its divisors is an integer number (1568600).

Almost surely, 2^21858768 is an apocalyptic number.

It is an amenable number.

21858768 is an abundant number, since it is smaller than the sum of its proper divisors (40885232).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21858768 is a wasteful number, since it uses less digits than its factorization.

21858768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50616 (or 50604 counting only the distinct ones).

The product of its digits is 215040, while the sum is 45.

The square root of 21858768 is about 4675.3361376483. The cubic root of 21858768 is about 279.6030429406.

The spelling of 21858768 in words is "twenty-one million, eight hundred fifty-eight thousand, seven hundred sixty-eight".