1999694539 has 6 divisors (see below), whose sum is σ = 2105146820. Its totient is φ = 1894262796.

The previous prime is 1999694537. The next prime is 1999694551. The reversal of 1999694539 is 9354969991.

It is not a de Polignac number, because 1999694539 - 2¹ = 1999694537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1999694533) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 189792 + ... + 200050.

Almost surely, 2^1999694539 is an apocalyptic number.

1999694539 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

1999694539 is a deficient number, since it is larger than the sum of its proper divisors (105452281).

1999694539 is an frugal number, since it uses more digits than its factorization.

1999694539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20537 (or 10278 counting only the distinct ones).

The product of its digits is 21257640, while the sum is 64.

The square root of 1999694539 is about 44717.9442617838. The cubic root of 1999694539 is about 1259.8569038384.

The spelling of 1999694539 in words is "one billion, nine hundred ninety-nine million, six hundred ninety-four thousand, five hundred thirty-nine".