87991619978 has 8 divisors (see below), whose sum is σ = 132563794980. Its totient is φ = 43803688320.

The previous prime is 87991619959. The next prime is 87991619981.

87991619978 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 2 ways, for example, as 86690791489 + 1300828489 = 294433^2 + 36067^2 .

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

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, 96060263 + ... + 96061178.

Almost surely, 2^87991619978 is an apocalyptic number.

87991619978 is a deficient number, since it is larger than the sum of its proper divisors (44572175002).

87991619978 is a wasteful number, since it uses less digits than its factorization.

87991619978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192121672.

The product of its digits is 123451776, while the sum is 74.

The spelling of 87991619978 in words is "eighty-seven billion, nine hundred ninety-one million, six hundred nineteen thousand, nine hundred seventy-eight".