21299983 has 2 divisors, whose sum is σ = 21299984. Its totient is φ = 21299982.

The previous prime is 21299959. The next prime is 21299987. The reversal of 21299983 is 38999212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21299983 - 2⁹ = 21299471 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21299987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10649991 + 10649992.

It is an arithmetic number, because the mean of its divisors is an integer number (10649992).

Almost surely, 2^21299983 is an apocalyptic number.

21299983 is a deficient number, since it is larger than the sum of its proper divisors (1).

21299983 is an equidigital number, since it uses as much as digits as its factorization.

21299983 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69984, while the sum is 43.

The square root of 21299983 is about 4615.1904619420. The cubic root of 21299983 is about 277.1999104284.

The spelling of 21299983 in words is "twenty-one million, two hundred ninety-nine thousand, nine hundred eighty-three".