21145012 has 48 divisors (see below), whose sum is σ = 43972992. Its totient is φ = 8709120.

The previous prime is 21145001. The next prime is 21145049. The reversal of 21145012 is 21054112.

It is a super-2 number, since 2×21145012² = 894223064960288, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 129643 + ... + 129805.

It is an arithmetic number, because the mean of its divisors is an integer number (916104).

Almost surely, 2^21145012 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21145012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21986496).

21145012 is an abundant number, since it is smaller than the sum of its proper divisors (22827980).

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

21145012 is a wasteful number, since it uses less digits than its factorization.

21145012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328 (or 326 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 21145012 is about 4598.3705809776. The cubic root of 21145012 is about 276.5260045281.

Adding to 21145012 its reverse (21054112), we get a palindrome (42199124).

The spelling of 21145012 in words is "twenty-one million, one hundred forty-five thousand, twelve".