21730036 has 12 divisors (see below), whose sum is σ = 38116512. Its totient is φ = 10839608.

The previous prime is 21730031. The next prime is 21730057. The reversal of 21730036 is 63003712.

It is a super-2 number, since 2×21730036² = 944388929122592, which contains 22 as substring.

It is a zygodrome in base 3.

It is a junction number, because it is equal to n+sod(n) for n = 21729989 and 21730016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21730031) 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 3 ways as a sum of consecutive naturals, for example, 4360 + ... + 7903.

It is an arithmetic number, because the mean of its divisors is an integer number (3176376).

Almost surely, 2^21730036 is an apocalyptic number.

It is an amenable number.

21730036 is a deficient number, since it is larger than the sum of its proper divisors (16386476).

21730036 is a wasteful number, since it uses less digits than its factorization.

21730036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12710 (or 12708 counting only the distinct ones).

The product of its (nonzero) digits is 756, while the sum is 22.

The square root of 21730036 is about 4661.5486697019. The cubic root of 21730036 is about 279.0530767501.

Adding to 21730036 its reverse (63003712), we get a palindrome (84733748).

The spelling of 21730036 in words is "twenty-one million, seven hundred thirty thousand, thirty-six".