21669533817 has 16 divisors (see below), whose sum is σ = 29911676160. Its totient is φ = 13945295232.

The previous prime is 21669533797. The next prime is 21669533827. The reversal of 21669533817 is 71833596612.

It is not a de Polignac number, because 21669533817 - 2⁷ = 21669533689 is a prime.

It is a super-2 number, since 2×21669533817² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21669533817.

It is not an unprimeable number, because it can be changed into a prime (21669533827) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1042342 + ... + 1062927.

It is an arithmetic number, because the mean of its divisors is an integer number (1869479760).

Almost surely, 2^21669533817 is an apocalyptic number.

It is an amenable number.

21669533817 is a deficient number, since it is larger than the sum of its proper divisors (8242142343).

21669533817 is a wasteful number, since it uses less digits than its factorization.

21669533817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2105392.

The product of its digits is 1632960, while the sum is 51.

The spelling of 21669533817 in words is "twenty-one billion, six hundred sixty-nine million, five hundred thirty-three thousand, eight hundred seventeen".