21243983 has 2 divisors, whose sum is σ = 21243984. Its totient is φ = 21243982.

The previous prime is 21243977. The next prime is 21243997. The reversal of 21243983 is 38934212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21243983 - 2¹⁰ = 21242959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21243913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621991 + 10621992.

It is an arithmetic number, because the mean of its divisors is an integer number (10621992).

Almost surely, 2^21243983 is an apocalyptic number.

21243983 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243983 is an equidigital number, since it uses as much as digits as its factorization.

21243983 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 32.

The square root of 21243983 is about 4609.1195471587. The cubic root of 21243983 is about 276.9567675277.

The spelling of 21243983 in words is "twenty-one million, two hundred forty-three thousand, nine hundred eighty-three".