21066345 has 64 divisors (see below), whose sum is σ = 40550400. Its totient is φ = 10342080.

The previous prime is 21066343. The next prime is 21066347. The reversal of 21066345 is 54366012.

21066345 is a `hidden beast` number, since 21 + 0 + 6 + 634 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (21066343) and next prime (21066347).

It is not a de Polignac number, because 21066345 - 2¹ = 21066343 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21066343) 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 63 ways as a sum of consecutive naturals, for example, 110200 + ... + 110390.

It is an arithmetic number, because the mean of its divisors is an integer number (633600).

Almost surely, 2^21066345 is an apocalyptic number.

It is an amenable number.

21066345 is a deficient number, since it is larger than the sum of its proper divisors (19484055).

21066345 is a wasteful number, since it uses less digits than its factorization.

21066345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 267 (or 261 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 21066345 is about 4589.8088195479. The cubic root of 21066345 is about 276.1826531979.

The spelling of 21066345 in words is "twenty-one million, sixty-six thousand, three hundred forty-five".