671026561 has 4 divisors (see below), whose sum is σ = 689162452. Its totient is φ = 652890672.

The previous prime is 671026547. The next prime is 671026571. The reversal of 671026561 is 165620176.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 617224336 + 53802225 = 24844^2 + 7335^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-671026561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (671026511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9067890 + ... + 9067963.

It is an arithmetic number, because the mean of its divisors is an integer number (172290613).

Almost surely, 2^671026561 is an apocalyptic number.

It is an amenable number.

671026561 is a deficient number, since it is larger than the sum of its proper divisors (18135891).

671026561 is a wasteful number, since it uses less digits than its factorization.

671026561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18135890.

The product of its (nonzero) digits is 15120, while the sum is 34.

The square root of 671026561 is about 25904.1803769199. The cubic root of 671026561 is about 875.4806876103.

The spelling of 671026561 in words is "six hundred seventy-one million, twenty-six thousand, five hundred sixty-one".