31720028919 has 4 divisors (see below), whose sum is σ = 42293371896. Its totient is φ = 21146685944.

The previous prime is 31720028911. The next prime is 31720028959. The reversal of 31720028919 is 91982002713.

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 31720028919 - 2³ = 31720028911 is a prime.

It is a super-2 number, since 2×31720028919² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31720028911) 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, 5286671484 + ... + 5286671489.

It is an arithmetic number, because the mean of its divisors is an integer number (10573342974).

Almost surely, 2^31720028919 is an apocalyptic number.

31720028919 is a deficient number, since it is larger than the sum of its proper divisors (10573342977).

31720028919 is a wasteful number, since it uses less digits than its factorization.

31720028919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10573342976.

The product of its (nonzero) digits is 54432, while the sum is 42.

The spelling of 31720028919 in words is "thirty-one billion, seven hundred twenty million, twenty-eight thousand, nine hundred nineteen".