21351332 has 12 divisors (see below), whose sum is σ = 37877196. Its totient is φ = 10529280.

The previous prime is 21351311. The next prime is 21351347. The reversal of 21351332 is 23315312.

It can be written as a sum of positive squares in 2 ways, for example, as 6031936 + 15319396 = 2456^2 + 3914^2 .

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, 36269 + ... + 36852.

It is an arithmetic number, because the mean of its divisors is an integer number (3156433).

Almost surely, 2^21351332 is an apocalyptic number.

It is an amenable number.

21351332 is a deficient number, since it is larger than the sum of its proper divisors (16525864).

21351332 is a wasteful number, since it uses less digits than its factorization.

21351332 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73198 (or 73196 counting only the distinct ones).

The product of its digits is 540, while the sum is 20.

The square root of 21351332 is about 4620.7501555483. The cubic root of 21351332 is about 277.4224851807.

Adding to 21351332 its reverse (23315312), we get a palindrome (44666644).

The spelling of 21351332 in words is "twenty-one million, three hundred fifty-one thousand, three hundred thirty-two".