7899779987 has 4 divisors (see below), whose sum is σ = 8617941816. Its totient is φ = 7181618160.

The previous prime is 7899779969. The next prime is 7899780019.

7899779987 is nontrivially palindromic in base 10.

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

It is a cyclic number.

It is not a de Polignac number, because 7899779987 - 2¹⁶ = 7899714451 is a prime.

It is not an unprimeable number, because it can be changed into a prime (7899779917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 359080898 + ... + 359080919.

It is an arithmetic number, because the mean of its divisors is an integer number (2154485454).

Almost surely, 2^7899779987 is an apocalyptic number.

7899779987 is a deficient number, since it is larger than the sum of its proper divisors (718161829).

7899779987 is a wasteful number, since it uses less digits than its factorization.

7899779987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 718161828.

The product of its digits is 1008189504, while the sum is 80.

The square root of 7899779987 is about 88880.7064947168. The cubic root of 7899779987 is about 1991.6132123054.

The spelling of 7899779987 in words is "seven billion, eight hundred ninety-nine million, seven hundred seventy-nine thousand, nine hundred eighty-seven".