21266056 has 16 divisors (see below), whose sum is σ = 45570240. Its totient is φ = 9114000.

The previous prime is 21266051. The next prime is 21266059. The reversal of 21266056 is 65066212.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is not an unprimeable number, because it can be changed into a prime (21266051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 189820 + ... + 189931.

It is an arithmetic number, because the mean of its divisors is an integer number (2848140).

Almost surely, 2^21266056 is an apocalyptic number.

It is an amenable number.

21266056 is an abundant number, since it is smaller than the sum of its proper divisors (24304184).

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

21266056 is a wasteful number, since it uses less digits than its factorization.

21266056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 379764 (or 379760 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 21266056 is about 4611.5134175236. The cubic root of 21266056 is about 277.0526558658.

The spelling of 21266056 in words is "twenty-one million, two hundred sixty-six thousand, fifty-six".