16991643903 has 32 divisors (see below), whose sum is σ = 25150712832. Its totient is φ = 10136016000.

The previous prime is 16991643901. The next prime is 16991643913. The reversal of 16991643903 is 30934619961.

It is a Cunningham number, because it is equal to 130352²-1.

It is not a de Polignac number, because 16991643903 - 2¹ = 16991643901 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16991643901) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 369328 + ... + 412778.

It is an arithmetic number, because the mean of its divisors is an integer number (785959776).

Almost surely, 2^16991643903 is an apocalyptic number.

16991643903 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

16991643903 is a deficient number, since it is larger than the sum of its proper divisors (8159068929).

16991643903 is a wasteful number, since it uses less digits than its factorization.

16991643903 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43775.

The product of its (nonzero) digits is 944784, while the sum is 51.

The spelling of 16991643903 in words is "sixteen billion, nine hundred ninety-one million, six hundred forty-three thousand, nine hundred three".