21317736 has 32 divisors (see below), whose sum is σ = 58140000. Its totient is φ = 6459840.

The previous prime is 21317729. The next prime is 21317749. The reversal of 21317736 is 63771312.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40111 + ... + 40638.

It is an arithmetic number, because the mean of its divisors is an integer number (1816875).

Almost surely, 2^21317736 is an apocalyptic number.

It is an amenable number.

21317736 is an abundant number, since it is smaller than the sum of its proper divisors (36822264).

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

21317736 is a wasteful number, since it uses less digits than its factorization.

21317736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80769 (or 80765 counting only the distinct ones).

The product of its digits is 5292, while the sum is 30.

The square root of 21317736 is about 4617.1133839229. The cubic root of 21317736 is about 277.2769020928.

The spelling of 21317736 in words is "twenty-one million, three hundred seventeen thousand, seven hundred thirty-six".