19439939993 has 4 divisors (see below), whose sum is σ = 19474841700. Its totient is φ = 19405038288.

The previous prime is 19439939989. The next prime is 19439939999. The reversal of 19439939993 is 39993993491.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 39993993491 = 37 ⋅1080918743.

It can be written as a sum of positive squares in 2 ways, for example, as 5644967689 + 13794972304 = 75133^2 + 117452^2 .

It is a cyclic number.

It is not a de Polignac number, because 19439939993 - 2² = 19439939989 is a prime.

It is a super-2 number, since 2×19439939993² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19439939999) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17450018 + ... + 17451131.

It is an arithmetic number, because the mean of its divisors is an integer number (4868710425).

Almost surely, 2^19439939993 is an apocalyptic number.

It is an amenable number.

19439939993 is a deficient number, since it is larger than the sum of its proper divisors (34901707).

19439939993 is an equidigital number, since it uses as much as digits as its factorization.

19439939993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34901706.

The product of its digits is 57395628, while the sum is 68.

The spelling of 19439939993 in words is "nineteen billion, four hundred thirty-nine million, nine hundred thirty-nine thousand, nine hundred ninety-three".