21781464080 has 40 divisors (see below), whose sum is σ = 50964493272. Its totient is φ = 8657086464.

The previous prime is 21781464059. The next prime is 21781464083. The reversal of 21781464080 is 8046418712.

It can be written as a sum of positive squares in 4 ways, for example, as 3847969024 + 17933495056 = 62032^2 + 133916^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (21781464083) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 854537 + ... + 879656.

Almost surely, 2^21781464080 is an apocalyptic number.

21781464080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21781464080 is an abundant number, since it is smaller than the sum of its proper divisors (29183029192).

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

21781464080 is a wasteful number, since it uses less digits than its factorization.

21781464080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1734363 (or 1734357 counting only the distinct ones).

The product of its (nonzero) digits is 86016, while the sum is 41.

The spelling of 21781464080 in words is "twenty-one billion, seven hundred eighty-one million, four hundred sixty-four thousand, eighty".