21983643 has 30 divisors (see below), whose sum is σ = 36112692. Its totient is φ = 13317480.

The previous prime is 21983641. The next prime is 21983671. The reversal of 21983643 is 34638912.

21983643 is a `hidden beast` number, since 2 + 1 + 9 + 8 + 3 + 643 = 666.

It is not a de Polignac number, because 21983643 - 2¹ = 21983641 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21983598 and 21983607.

It is not an unprimeable number, because it can be changed into a prime (21983641) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 8680 + ... + 10922.

Almost surely, 2^21983643 is an apocalyptic number.

21983643 is a deficient number, since it is larger than the sum of its proper divisors (14129049).

21983643 is a wasteful number, since it uses less digits than its factorization.

21983643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2277 (or 2257 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 21983643 is about 4688.6717735410. The cubic root of 21983643 is about 280.1344719732.

The spelling of 21983643 in words is "twenty-one million, nine hundred eighty-three thousand, six hundred forty-three".