21342280 has 32 divisors (see below), whose sum is σ = 48684600. Its totient is φ = 8418816.

The previous prime is 21342257. The next prime is 21342281. The reversal of 21342280 is 8224312.

It can be written as a sum of positive squares in 4 ways, for example, as 17156164 + 4186116 = 4142^2 + 2046^2 .

It is not an unprimeable number, because it can be changed into a prime (21342281) 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, 735 + ... + 6574.

Almost surely, 2^21342280 is an apocalyptic number.

21342280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21342280 is an abundant number, since it is smaller than the sum of its proper divisors (27342320).

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

21342280 is a wasteful number, since it uses less digits than its factorization.

21342280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7393 (or 7389 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 21342280 is about 4619.7705570732. The cubic root of 21342280 is about 277.3832747730.

Adding to 21342280 its reverse (8224312), we get a palindrome (29566592).

The spelling of 21342280 in words is "twenty-one million, three hundred forty-two thousand, two hundred eighty".