1987556979 has 8 divisors (see below), whose sum is σ = 2667626752. Its totient is φ = 1316262600.

The previous prime is 1987556957. The next prime is 1987556981. The reversal of 1987556979 is 9796557891.

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

It is a de Polignac number, because none of the positive numbers 2^k-1987556979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1987556929) 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, 2193319 + ... + 2194224.

It is an arithmetic number, because the mean of its divisors is an integer number (333453344).

Almost surely, 2^1987556979 is an apocalyptic number.

1987556979 is a deficient number, since it is larger than the sum of its proper divisors (680069773).

1987556979 is a wasteful number, since it uses less digits than its factorization.

1987556979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4387697.

The product of its digits is 42865200, while the sum is 66.

The square root of 1987556979 is about 44582.0252904688. The cubic root of 1987556979 is about 1257.3027417400.

The spelling of 1987556979 in words is "one billion, nine hundred eighty-seven million, five hundred fifty-six thousand, nine hundred seventy-nine".