6857511661 has 32 divisors (see below), whose sum is σ = 9456185088. Its totient is φ = 4799139840.

The previous prime is 6857511653. The next prime is 6857511691. The reversal of 6857511661 is 1661157586.

It is not a de Polignac number, because 6857511661 - 2³ = 6857511653 is a prime.

It is a Smith number, since the sum of its digits (46) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6857511611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 55540 + ... + 129613.

It is an arithmetic number, because the mean of its divisors is an integer number (295505784).

Almost surely, 2^6857511661 is an apocalyptic number.

It is an amenable number.

6857511661 is a deficient number, since it is larger than the sum of its proper divisors (2598673427).

6857511661 is a wasteful number, since it uses less digits than its factorization.

6857511661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185221.

The product of its digits is 302400, while the sum is 46.

The square root of 6857511661 is about 82810.0939559907. The cubic root of 6857511661 is about 1899.8625626348.

The spelling of 6857511661 in words is "six billion, eight hundred fifty-seven million, five hundred eleven thousand, six hundred sixty-one".