1981986578 has 16 divisors (see below), whose sum is σ = 3492732096. Its totient is φ = 831602640.

The previous prime is 1981986553. The next prime is 1981986703. The reversal of 1981986578 is 8756891891.

It is a self number, because there is not a number n which added to its sum of digits gives 1981986578.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3464726 + ... + 3465297.

It is an arithmetic number, because the mean of its divisors is an integer number (218295756).

Almost surely, 2^1981986578 is an apocalyptic number.

1981986578 is a deficient number, since it is larger than the sum of its proper divisors (1510745518).

1981986578 is a wasteful number, since it uses less digits than its factorization.

1981986578 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6930049.

The product of its digits is 8709120, while the sum is 62.

The square root of 1981986578 is about 44519.5078364530. The cubic root of 1981986578 is about 1256.1270549285.

The spelling of 1981986578 in words is "one billion, nine hundred eighty-one million, nine hundred eighty-six thousand, five hundred seventy-eight".