21369240 has 48 divisors (see below), whose sum is σ = 69451200. Its totient is φ = 5698368.

The previous prime is 21369223. The next prime is 21369247. The reversal of 21369240 is 4296312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21369247) 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, 29320 + ... + 30039.

It is an arithmetic number, because the mean of its divisors is an integer number (1446900).

Almost surely, 2^21369240 is an apocalyptic number.

21369240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21369240 is an abundant number, since it is smaller than the sum of its proper divisors (48081960).

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

21369240 is a wasteful number, since it uses less digits than its factorization.

21369240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59376 (or 59369 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 21369240 is about 4622.6875299981. The cubic root of 21369240 is about 277.5000243487.

It can be divided in two parts, 21369 and 240, that added together give a square (21609 = 147²).

The spelling of 21369240 in words is "twenty-one million, three hundred sixty-nine thousand, two hundred forty".