671286778820 has 144 divisors (see below), whose sum is σ = 1693714014720. Its totient is φ = 222605107200.

The previous prime is 671286778817. The next prime is 671286778823. The reversal of 671286778820 is 28877682176.

It is an interprime number because it is at equal distance from previous prime (671286778817) and next prime (671286778823).

It is a Harshad number since it is a multiple of its sum of digits (62).

It is not an unprimeable number, because it can be changed into a prime (671286778823) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 64734596 + ... + 64744964.

It is an arithmetic number, because the mean of its divisors is an integer number (11761902880).

Almost surely, 2^671286778820 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 671286778820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (846857007360).

671286778820 is an abundant number, since it is smaller than the sum of its proper divisors (1022427235900).

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

671286778820 is a wasteful number, since it uses less digits than its factorization.

671286778820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12554 (or 12545 counting only the distinct ones).

The product of its (nonzero) digits is 25288704, while the sum is 62.

The spelling of 671286778820 in words is "six hundred seventy-one billion, two hundred eighty-six million, seven hundred seventy-eight thousand, eight hundred twenty".