671221356 has 144 divisors (see below), whose sum is σ = 1787456160. Its totient is φ = 195686400.

The previous prime is 671221321. The next prime is 671221363. The reversal of 671221356 is 653122176.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5939956 + ... + 5940068.

It is an arithmetic number, because the mean of its divisors is an integer number (12412890).

Almost surely, 2^671221356 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 671221356, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (893728080).

671221356 is an abundant number, since it is smaller than the sum of its proper divisors (1116234804).

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

671221356 is a wasteful number, since it uses less digits than its factorization.

671221356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276 (or 261 counting only the distinct ones).

The product of its digits is 15120, while the sum is 33.

The square root of 671221356 is about 25907.9400184577. The cubic root of 671221356 is about 875.5653950178.

The spelling of 671221356 in words is "six hundred seventy-one million, two hundred twenty-one thousand, three hundred fifty-six".