21013012 has 12 divisors (see below), whose sum is σ = 38708320. Its totient is φ = 9953496.

The previous prime is 21012997. The next prime is 21013019. The reversal of 21013012 is 21031012.

It is a self number, because there is not a number n which added to its sum of digits gives 21013012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21013019) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 138168 + ... + 138319.

Almost surely, 2^21013012 is an apocalyptic number.

It is an amenable number.

21013012 is a deficient number, since it is larger than the sum of its proper divisors (17695308).

21013012 is a wasteful number, since it uses less digits than its factorization.

21013012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276510 (or 276508 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 21013012 is about 4583.9952006956. The cubic root of 21013012 is about 275.9493886053.

Adding to 21013012 its reverse (21031012), we get a palindrome (42044024).

The spelling of 21013012 in words is "twenty-one million, thirteen thousand, twelve".