21313332 has 36 divisors (see below), whose sum is σ = 55334916. Its totient is φ = 6912000.

The previous prime is 21313301. The next prime is 21313333. The reversal of 21313332 is 23331312.

21313332 is a `hidden beast` number, since 21 + 313 + 332 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 18610596 + 2702736 = 4314^2 + 1644^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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 a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21313333) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6669 + ... + 9332.

It is an arithmetic number, because the mean of its divisors is an integer number (1537081).

Almost surely, 2^21313332 is an apocalyptic number.

It is an amenable number.

21313332 is an abundant number, since it is smaller than the sum of its proper divisors (34021584).

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

21313332 is a wasteful number, since it uses less digits than its factorization.

21313332 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16048 (or 16043 counting only the distinct ones).

The product of its digits is 324, while the sum is 18.

The square root of 21313332 is about 4616.6364379275. The cubic root of 21313332 is about 277.2578067008.

Adding to 21313332 its reverse (23331312), we get a palindrome (44644644).

The spelling of 21313332 in words is "twenty-one million, three hundred thirteen thousand, three hundred thirty-two".