16920503721 has 32 divisors (see below), whose sum is σ = 27354931200. Its totient is φ = 10251602640.

The previous prime is 16920503687. The next prime is 16920503729. The reversal of 16920503721 is 12730502961.

16920503721 is a `hidden beast` number, since 1 + 69 + 20 + 503 + 72 + 1 = 666.

16920503721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 16920503721 - 2⁹ = 16920503209 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (16920503729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1204480 + ... + 1218446.

It is an arithmetic number, because the mean of its divisors is an integer number (854841600).

Almost surely, 2^16920503721 is an apocalyptic number.

16920503721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16920503721 is a deficient number, since it is larger than the sum of its proper divisors (10434427479).

16920503721 is a wasteful number, since it uses less digits than its factorization.

16920503721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18066 (or 18060 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 36.

The spelling of 16920503721 in words is "sixteen billion, nine hundred twenty million, five hundred three thousand, seven hundred twenty-one".