21240336 has 40 divisors (see below), whose sum is σ = 59093440. Its totient is φ = 6535296.

The previous prime is 21240313. The next prime is 21240377. The reversal of 21240336 is 63304212.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16396 + ... + 17643.

It is an arithmetic number, because the mean of its divisors is an integer number (1477336).

Almost surely, 2^21240336 is an apocalyptic number.

21240336 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21240336 is an abundant number, since it is smaller than the sum of its proper divisors (37853104).

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

21240336 is a wasteful number, since it uses less digits than its factorization.

21240336 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34063 (or 34057 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 21.

The square root of 21240336 is about 4608.7239014721. The cubic root of 21240336 is about 276.9409180338.

Adding to 21240336 its reverse (63304212), we get a palindrome (84544548).

The spelling of 21240336 in words is "twenty-one million, two hundred forty thousand, three hundred thirty-six".