21878567660 has 12 divisors (see below), whose sum is σ = 45944992128. Its totient is φ = 8751427056.

The previous prime is 21878567609. The next prime is 21878567663. The reversal of 21878567660 is 6676587812.

It is a junction number, because it is equal to n+sod(n) for n = 21878567596 and 21878567605.

It is not an unprimeable number, because it can be changed into a prime (21878567663) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 546964172 + ... + 546964211.

It is an arithmetic number, because the mean of its divisors is an integer number (3828749344).

Almost surely, 2^21878567660 is an apocalyptic number.

21878567660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21878567660 is an abundant number, since it is smaller than the sum of its proper divisors (24066424468).

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

21878567660 is a wasteful number, since it uses less digits than its factorization.

21878567660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1093928392 (or 1093928390 counting only the distinct ones).

The product of its (nonzero) digits is 6773760, while the sum is 56.

The spelling of 21878567660 in words is "twenty-one billion, eight hundred seventy-eight million, five hundred sixty-seven thousand, six hundred sixty".