21781024557448 has 32 divisors (see below), whose sum is σ = 44015302195200. Its totient is φ = 10044920628288.

The previous prime is 21781024557443. The next prime is 21781024557473. The reversal of 21781024557448 is 84475542018712.

It is a junction number, because it is equal to n+sod(n) for n = 21781024557392 and 21781024557401.

It is not an unprimeable number, because it can be changed into a prime (21781024557443) 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, 81740686 + ... + 82006717.

It is an arithmetic number, because the mean of its divisors is an integer number (1375478193600).

Almost surely, 2^{21781024557448} is an apocalyptic number.

It is an amenable number.

21781024557448 is an abundant number, since it is smaller than the sum of its proper divisors (22234277637752).

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

21781024557448 is a wasteful number, since it uses less digits than its factorization.

21781024557448 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163748701 (or 163748697 counting only the distinct ones).

The product of its (nonzero) digits is 20070400, while the sum is 58.

The spelling of 21781024557448 in words is "twenty-one trillion, seven hundred eighty-one billion, twenty-four million, five hundred fifty-seven thousand, four hundred forty-eight".