21665777099 has 8 divisors (see below), whose sum is σ = 22061037120. Its totient is φ = 21271451976.

The previous prime is 21665777051. The next prime is 21665777113. The reversal of 21665777099 is 99077756612.

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

It is a cyclic number.

It is not a de Polignac number, because 21665777099 - 2²⁰ = 21664728523 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (59).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21665777999) 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, 186869 + ... + 279734.

It is an arithmetic number, because the mean of its divisors is an integer number (2757629640).

Almost surely, 2^21665777099 is an apocalyptic number.

21665777099 is a deficient number, since it is larger than the sum of its proper divisors (395260021).

21665777099 is an equidigital number, since it uses as much as digits as its factorization.

21665777099 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 467449.

The product of its (nonzero) digits is 10001880, while the sum is 59.

The spelling of 21665777099 in words is "twenty-one billion, six hundred sixty-five million, seven hundred seventy-seven thousand, ninety-nine".