21665723466 has 8 divisors (see below), whose sum is σ = 43331446944. Its totient is φ = 7221907820.

The previous prime is 21665723459. The next prime is 21665723467. The reversal of 21665723466 is 66432756612.

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

21665723466 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (21665723467) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1805476950 + ... + 1805476961.

It is an arithmetic number, because the mean of its divisors is an integer number (5416430868).

Almost surely, 2^21665723466 is an apocalyptic number.

21665723466 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21665723466 is a wasteful number, since it uses less digits than its factorization.

21665723466 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3610953916.

The product of its digits is 2177280, while the sum is 48.

The spelling of 21665723466 in words is "twenty-one billion, six hundred sixty-five million, seven hundred twenty-three thousand, four hundred sixty-six".