1987208978 has 4 divisors (see below), whose sum is σ = 2980813470. Its totient is φ = 993604488.

The previous prime is 1987208953. The next prime is 1987208981. The reversal of 1987208978 is 8798027891.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 1430579329 + 556629649 = 37823^2 + 23593^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 496802243 + ... + 496802246.

Almost surely, 2^1987208978 is an apocalyptic number.

1987208978 is a deficient number, since it is larger than the sum of its proper divisors (993604492).

1987208978 is an equidigital number, since it uses as much as digits as its factorization.

1987208978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 993604491.

The product of its (nonzero) digits is 4064256, while the sum is 59.

The square root of 1987208978 is about 44578.1221901506. The cubic root of 1987208978 is about 1257.2293571519.

The spelling of 1987208978 in words is "one billion, nine hundred eighty-seven million, two hundred eight thousand, nine hundred seventy-eight".