671605651 has 4 divisors (see below), whose sum is σ = 675883552. Its totient is φ = 667327752.

The previous prime is 671605643. The next prime is 671605657. The reversal of 671605651 is 156506176.

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

It is a cyclic number.

It is not a de Polignac number, because 671605651 - 2³ = 671605643 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 671605651.

It is not an unprimeable number, because it can be changed into a prime (671605657) 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, 2138715 + ... + 2139028.

It is an arithmetic number, because the mean of its divisors is an integer number (168970888).

Almost surely, 2^671605651 is an apocalyptic number.

671605651 is a deficient number, since it is larger than the sum of its proper divisors (4277901).

671605651 is a wasteful number, since it uses less digits than its factorization.

671605651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4277900.

The product of its (nonzero) digits is 37800, while the sum is 37.

The square root of 671605651 is about 25915.3555059544. The cubic root of 671605651 is about 875.7324592342.

The spelling of 671605651 in words is "six hundred seventy-one million, six hundred five thousand, six hundred fifty-one".