21288684416 has 32 divisors (see below), whose sum is σ = 42501986280. Its totient is φ = 10621519360.

The previous prime is 21288684383. The next prime is 21288684419. The reversal of 21288684416 is 61448688212.

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×21288684416² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21288684419) 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 3 ways as a sum of consecutive naturals, for example, 118295 + ... + 237846.

Almost surely, 2^21288684416 is an apocalyptic number.

It is an amenable number.

21288684416 is a deficient number, since it is larger than the sum of its proper divisors (21213301864).

21288684416 is an equidigital number, since it uses as much as digits as its factorization.

21288684416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 356622 (or 356610 counting only the distinct ones).

The product of its digits is 1179648, while the sum is 50.

The spelling of 21288684416 in words is "twenty-one billion, two hundred eighty-eight million, six hundred eighty-four thousand, four hundred sixteen".