21113316 has 54 divisors (see below), whose sum is σ = 62088390. Its totient is φ = 6031872.

The previous prime is 21113299. The next prime is 21113317. The reversal of 21113316 is 61331112.

It can be written as a sum of positive squares in only one way, i.e., 13660416 + 7452900 = 3696^2 + 2730^2 .

It is a super-2 number, since 2×21113316² = 891544225031712, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21113317) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 4221 + ... + 7748.

It is an arithmetic number, because the mean of its divisors is an integer number (1149785).

Almost surely, 2^21113316 is an apocalyptic number.

It is an amenable number.

21113316 is an abundant number, since it is smaller than the sum of its proper divisors (40975074).

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

21113316 is a wasteful number, since it uses less digits than its factorization.

21113316 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11993 (or 11981 counting only the distinct ones).

The product of its digits is 108, while the sum is 18.

The square root of 21113316 is about 4594.9228502772. The cubic root of 21113316 is about 276.3877662318.

Adding to 21113316 its reverse (61331112), we get a palindrome (82444428).

The spelling of 21113316 in words is "twenty-one million, one hundred thirteen thousand, three hundred sixteen".