2178287395891 has 16 divisors (see below), whose sum is σ = 2266213140000. Its totient is φ = 2091218139136.

The previous prime is 2178287395873. The next prime is 2178287395897. The reversal of 2178287395891 is 1985937828712.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 2178287395891 - 2³⁹ = 1628531582003 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2178287395891.

It is not an unprimeable number, because it can be changed into a prime (2178287395897) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 92019405 + ... + 92043073.

It is an arithmetic number, because the mean of its divisors is an integer number (141638321250).

Almost surely, 2^{2178287395891} is an apocalyptic number.

2178287395891 is a deficient number, since it is larger than the sum of its proper divisors (87925744109).

2178287395891 is a wasteful number, since it uses less digits than its factorization.

2178287395891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41606.

The product of its digits is 121927680, while the sum is 70.

The spelling of 2178287395891 in words is "two trillion, one hundred seventy-eight billion, two hundred eighty-seven million, three hundred ninety-five thousand, eight hundred ninety-one".