864205991 has 8 divisors (see below), whose sum is σ = 943033104. Its totient is φ = 785422720.

The previous prime is 864205987. The next prime is 864206009. The reversal of 864205991 is 199502468.

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 864205991 - 2² = 864205987 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 (864205961) 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, 40991 + ... + 58383.

It is an arithmetic number, because the mean of its divisors is an integer number (117879138).

Almost surely, 2^864205991 is an apocalyptic number.

864205991 is a deficient number, since it is larger than the sum of its proper divisors (78827113).

864205991 is a wasteful number, since it uses less digits than its factorization.

864205991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21921.

The product of its (nonzero) digits is 155520, while the sum is 44.

The square root of 864205991 is about 29397.3806826391. The cubic root of 864205991 is about 952.5163173724.

The spelling of 864205991 in words is "eight hundred sixty-four million, two hundred five thousand, nine hundred ninety-one".