1994723287578 has 36 divisors (see below), whose sum is σ = 5027516859690. Its totient is φ = 569920939056.

The previous prime is 1994723287577. The next prime is 1994723287631. The reversal of 1994723287578 is 8757823274991.

It is a happy number.

1994723287578 is a `hidden beast` number, since 1 + 9 + 9 + 4 + 7 + 23 + 28 + 7 + 578 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1824841651689 + 169881635889 = 1350867^2 + 412167^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1994723287577) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1130794633 + ... + 1130796396.

Almost surely, 2^{1994723287578} is an apocalyptic number.

1994723287578 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1994723287578 is an abundant number, since it is smaller than the sum of its proper divisors (3032793572112).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1994723287578 is a wasteful number, since it uses less digits than its factorization.

1994723287578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2261591051 (or 2261591041 counting only the distinct ones).

The product of its digits is 426746880, while the sum is 72.

The spelling of 1994723287578 in words is "one trillion, nine hundred ninety-four billion, seven hundred twenty-three million, two hundred eighty-seven thousand, five hundred seventy-eight".