21036999 has 4 divisors (see below), whose sum is σ = 28049336. Its totient is φ = 14024664.

The previous prime is 21036991. The next prime is 21037013. The reversal of 21036999 is 99963012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21036999 - 2³ = 21036991 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21036991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3506164 + ... + 3506169.

It is an arithmetic number, because the mean of its divisors is an integer number (7012334).

Almost surely, 2^21036999 is an apocalyptic number.

21036999 is a deficient number, since it is larger than the sum of its proper divisors (7012337).

21036999 is an equidigital number, since it uses as much as digits as its factorization.

21036999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7012336.

The product of its (nonzero) digits is 26244, while the sum is 39.

The square root of 21036999 is about 4586.6108402610. The cubic root of 21036999 is about 276.0543502502.

The spelling of 21036999 in words is "twenty-one million, thirty-six thousand, nine hundred ninety-nine".