16640373991 has 2 divisors, whose sum is σ = 16640373992. Its totient is φ = 16640373990.

The previous prime is 16640373989. The next prime is 16640374031. The reversal of 16640373991 is 19937304661.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (19937304661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16640373991 - 2¹ = 16640373989 is a prime.

Together with 16640373989, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16640373931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8320186995 + 8320186996.

It is an arithmetic number, because the mean of its divisors is an integer number (8320186996).

Almost surely, 2^16640373991 is an apocalyptic number.

16640373991 is a deficient number, since it is larger than the sum of its proper divisors (1).

16640373991 is an equidigital number, since it uses as much as digits as its factorization.

16640373991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 734832, while the sum is 49.

The spelling of 16640373991 in words is "sixteen billion, six hundred forty million, three hundred seventy-three thousand, nine hundred ninety-one".