1987694243 has 4 divisors (see below), whose sum is σ = 2005930080. Its totient is φ = 1969458408.

The previous prime is 1987694231. The next prime is 1987694257. The reversal of 1987694243 is 3424967891.

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 1987694243 - 2¹⁶ = 1987628707 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1987694263) 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, 9117755 + ... + 9117972.

It is an arithmetic number, because the mean of its divisors is an integer number (501482520).

Almost surely, 2^1987694243 is an apocalyptic number.

1987694243 is a deficient number, since it is larger than the sum of its proper divisors (18235837).

1987694243 is a wasteful number, since it uses less digits than its factorization.

1987694243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18235836.

The product of its digits is 2612736, while the sum is 53.

The square root of 1987694243 is about 44583.5647184027. The cubic root of 1987694243 is about 1257.3316848818.

The spelling of 1987694243 in words is "one billion, nine hundred eighty-seven million, six hundred ninety-four thousand, two hundred forty-three".