21299766 has 16 divisors (see below), whose sum is σ = 42816000. Its totient is φ = 7063848.

The previous prime is 21299737. The next prime is 21299783. The reversal of 21299766 is 66799212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7726 + ... + 10113.

It is an arithmetic number, because the mean of its divisors is an integer number (2676000).

Almost surely, 2^21299766 is an apocalyptic number.

21299766 is an abundant number, since it is smaller than the sum of its proper divisors (21516234).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21299766 is a wasteful number, since it uses less digits than its factorization.

21299766 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18043.

The product of its digits is 81648, while the sum is 42.

The square root of 21299766 is about 4615.1669525598. The cubic root of 21299766 is about 277.1989690726.

The spelling of 21299766 in words is "twenty-one million, two hundred ninety-nine thousand, seven hundred sixty-six".