1670561857 has 4 divisors (see below), whose sum is σ = 1693446340. Its totient is φ = 1647677376.

The previous prime is 1670561819. The next prime is 1670561861. The reversal of 1670561857 is 7581650761.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7581650761 = 109 ⋅69556429.

It can be written as a sum of positive squares in 2 ways, for example, as 729054001 + 941507856 = 27001^2 + 30684^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1670561857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1670561897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11442132 + ... + 11442277.

It is an arithmetic number, because the mean of its divisors is an integer number (423361585).

Almost surely, 2^1670561857 is an apocalyptic number.

It is an amenable number.

1670561857 is a deficient number, since it is larger than the sum of its proper divisors (22884483).

1670561857 is an equidigital number, since it uses as much as digits as its factorization.

1670561857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22884482.

The product of its (nonzero) digits is 352800, while the sum is 46.

The square root of 1670561857 is about 40872.5073490727. The cubic root of 1670561857 is about 1186.5540346307.

The spelling of 1670561857 in words is "one billion, six hundred seventy million, five hundred sixty-one thousand, eight hundred fifty-seven".