21303999 has 16 divisors (see below), whose sum is σ = 31645440. Its totient is φ = 14164920.

The previous prime is 21303979. The next prime is 21304001. The reversal of 21303999 is 99930312.

It is not a de Polignac number, because 21303999 - 2⁵ = 21303967 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21303979) 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 15 ways as a sum of consecutive naturals, for example, 12454 + ... + 14060.

It is an arithmetic number, because the mean of its divisors is an integer number (1977840).

Almost surely, 2^21303999 is an apocalyptic number.

21303999 is a deficient number, since it is larger than the sum of its proper divisors (10341441).

21303999 is a wasteful number, since it uses less digits than its factorization.

21303999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2107 (or 2101 counting only the distinct ones).

The product of its (nonzero) digits is 13122, while the sum is 36.

The square root of 21303999 is about 4615.6255264048. The cubic root of 21303999 is about 277.2173308630.

The spelling of 21303999 in words is "twenty-one million, three hundred three thousand, nine hundred ninety-nine".