19939493971 has 4 divisors (see below), whose sum is σ = 19988246200. Its totient is φ = 19890741744.

The previous prime is 19939493957. The next prime is 19939493999. The reversal of 19939493971 is 17939493991.

It is a happy number.

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 19939493971 - 2⁵ = 19939493939 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19939493941) 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, 24375501 + ... + 24376318.

It is an arithmetic number, because the mean of its divisors is an integer number (4997061550).

Almost surely, 2^19939493971 is an apocalyptic number.

19939493971 is a deficient number, since it is larger than the sum of its proper divisors (48752229).

19939493971 is an equidigital number, since it uses as much as digits as its factorization.

19939493971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48752228.

The product of its digits is 14880348, while the sum is 64.

The spelling of 19939493971 in words is "nineteen billion, nine hundred thirty-nine million, four hundred ninety-three thousand, nine hundred seventy-one".