21167983 has 4 divisors (see below), whose sum is σ = 21310200. Its totient is φ = 21025768.

The previous prime is 21167969. The next prime is 21167987. The reversal of 21167983 is 38976112.

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 21167983 - 2¹³ = 21159791 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21167987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70885 + ... + 71182.

It is an arithmetic number, because the mean of its divisors is an integer number (5327550).

Almost surely, 2^21167983 is an apocalyptic number.

21167983 is a deficient number, since it is larger than the sum of its proper divisors (142217).

21167983 is a wasteful number, since it uses less digits than its factorization.

21167983 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142216.

The product of its digits is 18144, while the sum is 37.

The square root of 21167983 is about 4600.8676355661. The cubic root of 21167983 is about 276.6261034707.

The spelling of 21167983 in words is "twenty-one million, one hundred sixty-seven thousand, nine hundred eighty-three".