21491494066 has 8 divisors (see below), whose sum is σ = 36842561280. Its totient is φ = 9210640308.

The previous prime is 21491494019. The next prime is 21491494081. The reversal of 21491494066 is 66049419412.

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 767553346 + ... + 767553373.

It is an arithmetic number, because the mean of its divisors is an integer number (4605320160).

Almost surely, 2^21491494066 is an apocalyptic number.

21491494066 is a deficient number, since it is larger than the sum of its proper divisors (15351067214).

21491494066 is a wasteful number, since it uses less digits than its factorization.

21491494066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1535106728.

The product of its (nonzero) digits is 373248, while the sum is 46.

The spelling of 21491494066 in words is "twenty-one billion, four hundred ninety-one million, four hundred ninety-four thousand, sixty-six".