39981940091 has 4 divisors (see below), whose sum is σ = 39982768800. Its totient is φ = 39981111384.

The previous prime is 39981940079. The next prime is 39981940121. The reversal of 39981940091 is 19004918993.

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 39981940091 - 2³⁰ = 38908198267 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (39981940891) 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, 337196 + ... + 440073.

It is an arithmetic number, because the mean of its divisors is an integer number (9995692200).

Almost surely, 2^39981940091 is an apocalyptic number.

39981940091 is a deficient number, since it is larger than the sum of its proper divisors (828709).

39981940091 is an equidigital number, since it uses as much as digits as its factorization.

39981940091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 828708.

The product of its (nonzero) digits is 629856, while the sum is 53.

The spelling of 39981940091 in words is "thirty-nine billion, nine hundred eighty-one million, nine hundred forty thousand, ninety-one".