671907640 has 128 divisors (see below), whose sum is σ = 1668096000. Its totient is φ = 243285120.

The previous prime is 671907617. The next prime is 671907667. The reversal of 671907640 is 46709176.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 671907593 and 671907602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8505121 + ... + 8505199.

It is an arithmetic number, because the mean of its divisors is an integer number (13032000).

Almost surely, 2^671907640 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 671907640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (834048000).

671907640 is an abundant number, since it is smaller than the sum of its proper divisors (996188360).

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

671907640 is a wasteful number, since it uses less digits than its factorization.

671907640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178 (or 136 counting only the distinct ones).

The product of its (nonzero) digits is 63504, while the sum is 40.

The square root of 671907640 is about 25921.1813002417. The cubic root of 671907640 is about 875.8636979260.

The spelling of 671907640 in words is "six hundred seventy-one million, nine hundred seven thousand, six hundred forty".