1990439518 has 4 divisors (see below), whose sum is σ = 2985659280. Its totient is φ = 995219758.

The previous prime is 1990439501. The next prime is 1990439533. The reversal of 1990439518 is 8159340991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8159340991 = 1913 ⋅4265207.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 497609878 + ... + 497609881.

It is an arithmetic number, because the mean of its divisors is an integer number (746414820).

Almost surely, 2^1990439518 is an apocalyptic number.

1990439518 is a deficient number, since it is larger than the sum of its proper divisors (995219762).

1990439518 is an equidigital number, since it uses as much as digits as its factorization.

1990439518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 995219761.

The product of its (nonzero) digits is 349920, while the sum is 49.

The square root of 1990439518 is about 44614.3420662011. The cubic root of 1990439518 is about 1257.9102670545.

The spelling of 1990439518 in words is "one billion, nine hundred ninety million, four hundred thirty-nine thousand, five hundred eighteen".