1987694979 has 4 divisors (see below), whose sum is σ = 2650259976. Its totient is φ = 1325129984.

The previous prime is 1987694957. The next prime is 1987694999. The reversal of 1987694979 is 9794967891.

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 1987694979 - 2¹² = 1987690883 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1987694999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 331282494 + ... + 331282499.

It is an arithmetic number, because the mean of its divisors is an integer number (662564994).

Almost surely, 2^1987694979 is an apocalyptic number.

1987694979 is a deficient number, since it is larger than the sum of its proper divisors (662564997).

1987694979 is an equidigital number, since it uses as much as digits as its factorization.

1987694979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 662564996.

The product of its digits is 61725888, while the sum is 69.

The square root of 1987694979 is about 44583.5729725647. The cubic root of 1987694979 is about 1257.3318400693.

The spelling of 1987694979 in words is "one billion, nine hundred eighty-seven million, six hundred ninety-four thousand, nine hundred seventy-nine".