21282660 has 216 divisors, whose sum is σ = 79672320. Its totient is φ = 4572288.

The previous prime is 21282643. The next prime is 21282661. The reversal of 21282660 is 6628212.

It is not an unprimeable number, because it can be changed into a prime (21282661) by changing a digit.

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 71 ways as a sum of consecutive naturals, for example, 167517 + ... + 167643.

Almost surely, 2^21282660 is an apocalyptic number.

21282660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21282660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39836160).

21282660 is an abundant number, since it is smaller than the sum of its proper divisors (58389660).

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

21282660 is a wasteful number, since it uses less digits than its factorization.

21282660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175 (or 163 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 21282660 is about 4613.3133429239. The cubic root of 21282660 is about 277.1247423493.

The spelling of 21282660 in words is "twenty-one million, two hundred eighty-two thousand, six hundred sixty".