21225340 has 24 divisors (see below), whose sum is σ = 44805600. Its totient is φ = 8445888.

The previous prime is 21225329. The next prime is 21225349. The reversal of 21225340 is 4352212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21225349) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1314 + ... + 6646.

It is an arithmetic number, because the mean of its divisors is an integer number (1866900).

Almost surely, 2^21225340 is an apocalyptic number.

21225340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21225340 is an abundant number, since it is smaller than the sum of its proper divisors (23580260).

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

21225340 is a wasteful number, since it uses less digits than its factorization.

21225340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5541 (or 5539 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 21225340 is about 4607.0966996580. The cubic root of 21225340 is about 276.8757278574.

Adding to 21225340 its reverse (4352212), we get a palindrome (25577552).

It can be divided in two parts, 212 and 25340, that added together give a palindrome (25552).

The spelling of 21225340 in words is "twenty-one million, two hundred twenty-five thousand, three hundred forty".