21012936 has 128 divisors (see below), whose sum is σ = 65664000. Its totient is φ = 5467392.

The previous prime is 21012913. The next prime is 21012991. The reversal of 21012936 is 63921012.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 92455 + ... + 92681.

It is an arithmetic number, because the mean of its divisors is an integer number (513000).

Almost surely, 2^21012936 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 21012936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32832000).

21012936 is an abundant number, since it is smaller than the sum of its proper divisors (44651064).

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

21012936 is a wasteful number, since it uses less digits than its factorization.

21012936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291 (or 287 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 21012936 is about 4583.9869109761. The cubic root of 21012936 is about 275.9490559197.

Adding to 21012936 its reverse (63921012), we get a palindrome (84933948).

The spelling of 21012936 in words is "twenty-one million, twelve thousand, nine hundred thirty-six".