87978487978 has 4 divisors (see below), whose sum is σ = 131967731970. Its totient is φ = 43989243988.

The previous prime is 87978487969. The next prime is 87978487997.

87978487978 is nontrivially palindromic in base 10.

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., 76520284129 + 11458203849 = 276623^2 + 107043^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21994621993 + ... + 21994621996.

Almost surely, 2^87978487978 is an apocalyptic number.

87978487978 is a deficient number, since it is larger than the sum of its proper divisors (43989243992).

87978487978 is a wasteful number, since it uses less digits than its factorization.

87978487978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43989243991.

The product of its digits is 3186376704, while the sum is 82.

The spelling of 87978487978 in words is "eighty-seven billion, nine hundred seventy-eight million, four hundred eighty-seven thousand, nine hundred seventy-eight".