855660691 has 4 divisors (see below), whose sum is σ = 862192584. Its totient is φ = 849128800.

The previous prime is 855660653. The next prime is 855660713. The reversal of 855660691 is 196066558.

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 855660691 - 2⁷ = 855660563 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (855660601) 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, 3265750 + ... + 3266011.

It is an arithmetic number, because the mean of its divisors is an integer number (215548146).

Almost surely, 2^855660691 is an apocalyptic number.

855660691 is a deficient number, since it is larger than the sum of its proper divisors (6531893).

855660691 is a wasteful number, since it uses less digits than its factorization.

855660691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6531892.

The product of its (nonzero) digits is 388800, while the sum is 46.

The square root of 855660691 is about 29251.6784304764. The cubic root of 855660691 is about 949.3664070731.

The spelling of 855660691 in words is "eight hundred fifty-five million, six hundred sixty thousand, six hundred ninety-one".