21016730 has 16 divisors (see below), whose sum is σ = 43234560. Its totient is φ = 7205712.

The previous prime is 21016693. The next prime is 21016739. The reversal of 21016730 is 3761012.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21016739) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 150050 + ... + 150189.

It is an arithmetic number, because the mean of its divisors is an integer number (2702160).

Almost surely, 2^21016730 is an apocalyptic number.

21016730 is an abundant number, since it is smaller than the sum of its proper divisors (22217830).

21016730 is a wasteful number, since it uses less digits than its factorization.

21016730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 300253.

The product of its (nonzero) digits is 252, while the sum is 20.

The square root of 21016730 is about 4584.4007241950. The cubic root of 21016730 is about 275.9656629551.

Adding to 21016730 its reverse (3761012), we get a palindrome (24777742).

The spelling of 21016730 in words is "twenty-one million, sixteen thousand, seven hundred thirty".