16500601991 has 2 divisors, whose sum is σ = 16500601992. Its totient is φ = 16500601990.

The previous prime is 16500601979. The next prime is 16500602057. The reversal of 16500601991 is 19910600561.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16500601991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16500601951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8250300995 + 8250300996.

It is an arithmetic number, because the mean of its divisors is an integer number (8250300996).

Almost surely, 2^16500601991 is an apocalyptic number.

16500601991 is a deficient number, since it is larger than the sum of its proper divisors (1).

16500601991 is an equidigital number, since it uses as much as digits as its factorization.

16500601991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14580, while the sum is 38.

The spelling of 16500601991 in words is "sixteen billion, five hundred million, six hundred one thousand, nine hundred ninety-one".