21609260 has 12 divisors (see below), whose sum is σ = 45379488. Its totient is φ = 8643696.

The previous prime is 21609239. The next prime is 21609277. The reversal of 21609260 is 6290612.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 540212 + ... + 540251.

It is an arithmetic number, because the mean of its divisors is an integer number (3781624).

Almost surely, 2^21609260 is an apocalyptic number.

21609260 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21609260 is an abundant number, since it is smaller than the sum of its proper divisors (23770228).

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

21609260 is a wasteful number, since it uses less digits than its factorization.

21609260 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1080472 (or 1080470 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 21609260 is about 4648.5761260842. The cubic root of 21609260 is about 278.5351216575.

Adding to 21609260 its reverse (6290612), we get a palindrome (27899872).

The spelling of 21609260 in words is "twenty-one million, six hundred nine thousand, two hundred sixty".