21858983 has 4 divisors (see below), whose sum is σ = 22166928. Its totient is φ = 21551040.

The previous prime is 21858979. The next prime is 21858989. The reversal of 21858983 is 38985812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21858983 - 2² = 21858979 is a prime.

It is a super-3 number, since 3×21858983³ (a number of 23 digits) contains 333 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21858989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 153866 + ... + 154007.

It is an arithmetic number, because the mean of its divisors is an integer number (5541732).

Almost surely, 2^21858983 is an apocalyptic number.

21858983 is a deficient number, since it is larger than the sum of its proper divisors (307945).

21858983 is an equidigital number, since it uses as much as digits as its factorization.

21858983 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307944.

The product of its digits is 138240, while the sum is 44.

The square root of 21858983 is about 4675.3591305909. The cubic root of 21858983 is about 279.6039596507.

The spelling of 21858983 in words is "twenty-one million, eight hundred fifty-eight thousand, nine hundred eighty-three".