21749030666 has 16 divisors (see below), whose sum is σ = 36120509280. Its totient is φ = 9738371280.

The previous prime is 21749030663. The next prime is 21749030669. The reversal of 21749030666 is 66603094712.

It is an interprime number because it is at equal distance from previous prime (21749030663) and next prime (21749030669).

It is not an unprimeable number, because it can be changed into a prime (21749030663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7376081 + ... + 7379028.

It is an arithmetic number, because the mean of its divisors is an integer number (2257531830).

Almost surely, 2^21749030666 is an apocalyptic number.

21749030666 is a deficient number, since it is larger than the sum of its proper divisors (14371478614).

21749030666 is a wasteful number, since it uses less digits than its factorization.

21749030666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14755189.

The product of its (nonzero) digits is 326592, while the sum is 44.

The spelling of 21749030666 in words is "twenty-one billion, seven hundred forty-nine million, thirty thousand, six hundred sixty-six".