21299993 has 16 divisors (see below), whose sum is σ = 25251072. Its totient is φ = 17859600.

The previous prime is 21299987. The next prime is 21300029. The reversal of 21299993 is 39999212.

It is not a de Polignac number, because 21299993 - 2⁸ = 21299737 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21299923) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16688 + ... + 17918.

It is an arithmetic number, because the mean of its divisors is an integer number (1578192).

Almost surely, 2^21299993 is an apocalyptic number.

It is an amenable number.

21299993 is a deficient number, since it is larger than the sum of its proper divisors (3951079).

21299993 is a wasteful number, since it uses less digits than its factorization.

21299993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1277 (or 1255 counting only the distinct ones).

The product of its digits is 78732, while the sum is 44.

The square root of 21299993 is about 4615.1915453207. The cubic root of 21299993 is about 277.1999538087.

The spelling of 21299993 in words is "twenty-one million, two hundred ninety-nine thousand, nine hundred ninety-three".