2185864591991 has 8 divisors (see below), whose sum is σ = 2187855589920. Its totient is φ = 2183874102432.

The previous prime is 2185864591973. The next prime is 2185864591993. The reversal of 2185864591991 is 1991954685812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2185864591991 - 2⁶ = 2185864591927 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2185864591993) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8757761 + ... + 9003893.

It is an arithmetic number, because the mean of its divisors is an integer number (273481948740).

Almost surely, 2^{2185864591991} is an apocalyptic number.

2185864591991 is a deficient number, since it is larger than the sum of its proper divisors (1990997929).

2185864591991 is a wasteful number, since it uses less digits than its factorization.

2185864591991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254185.

The product of its digits is 55987200, while the sum is 68.

The spelling of 2185864591991 in words is "two trillion, one hundred eighty-five billion, eight hundred sixty-four million, five hundred ninety-one thousand, nine hundred ninety-one".