21037816 has 16 divisors (see below), whose sum is σ = 39606840. Its totient is φ = 10476000.

The previous prime is 21037813. The next prime is 21037817. The reversal of 21037816 is 61873012.

It is a super-3 number, since 3×21037816³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21037813) 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, 3231 + ... + 7246.

Almost surely, 2^21037816 is an apocalyptic number.

It is an amenable number.

21037816 is a deficient number, since it is larger than the sum of its proper divisors (18569024).

21037816 is a wasteful number, since it uses less digits than its factorization.

21037816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10734 (or 10730 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 21037816 is about 4586.6999029804. The cubic root of 21037816 is about 276.0579238506.

The spelling of 21037816 in words is "twenty-one million, thirty-seven thousand, eight hundred sixteen".