21136736 has 24 divisors (see below), whose sum is σ = 42583464. Its totient is φ = 10321920.

The previous prime is 21136723. The next prime is 21136751. The reversal of 21136736 is 63763112.

It is a junction number, because it is equal to n+sod(n) for n = 21136699 and 21136708.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6305 + ... + 9056.

It is an arithmetic number, because the mean of its divisors is an integer number (1774311).

Almost surely, 2^21136736 is an apocalyptic number.

It is an amenable number.

21136736 is an abundant number, since it is smaller than the sum of its proper divisors (21446728).

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

21136736 is a wasteful number, since it uses less digits than its factorization.

21136736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15414 (or 15406 counting only the distinct ones).

The product of its digits is 4536, while the sum is 29.

The square root of 21136736 is about 4597.4706089327. The cubic root of 21136736 is about 276.4899230817.

Adding to 21136736 its reverse (63763112), we get a palindrome (84899848).

The spelling of 21136736 in words is "twenty-one million, one hundred thirty-six thousand, seven hundred thirty-six".