21066355 has 8 divisors (see below), whose sum is σ = 25334064. Its totient is φ = 16816800.

The previous prime is 21066347. The next prime is 21066359. The reversal of 21066355 is 55366012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21066355 - 2³ = 21066347 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21066359) 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, 1836 + ... + 6745.

It is an arithmetic number, because the mean of its divisors is an integer number (3166758).

Almost surely, 2^21066355 is an apocalyptic number.

21066355 is a deficient number, since it is larger than the sum of its proper divisors (4267709).

21066355 is an equidigital number, since it uses as much as digits as its factorization.

21066355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9077.

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 21066355 is about 4589.8099089178. The cubic root of 21066355 is about 276.1826968984.

The spelling of 21066355 in words is "twenty-one million, sixty-six thousand, three hundred fifty-five".