1998056978 has 8 divisors (see below), whose sum is σ = 2997581772. Its totient is φ = 998863056.

The previous prime is 1998056947. The next prime is 1998057001. The reversal of 1998056978 is 8796508991.

It can be written as a sum of positive squares in 2 ways, for example, as 1867709089 + 130347889 = 43217^2 + 11417^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 1998056978.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67025 + ... + 92132.

Almost surely, 2^1998056978 is an apocalyptic number.

1998056978 is a deficient number, since it is larger than the sum of its proper divisors (999524794).

1998056978 is a wasteful number, since it uses less digits than its factorization.

1998056978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165436.

The product of its (nonzero) digits is 9797760, while the sum is 62.

The square root of 1998056978 is about 44699.6306248721. The cubic root of 1998056978 is about 1259.5129086421.

The spelling of 1998056978 in words is "one billion, nine hundred ninety-eight million, fifty-six thousand, nine hundred seventy-eight".