16991973 has 12 divisors (see below), whose sum is σ = 24724908. Its totient is φ = 11244480.

The previous prime is 16991951. The next prime is 16992007. The reversal of 16991973 is 37919961.

It can be written as a sum of positive squares in 2 ways, for example, as 9847044 + 7144929 = 3138^2 + 2673^2 .

It is not a de Polignac number, because 16991973 - 2¹⁸ = 16729829 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16991173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5658 + ... + 8123.

It is an arithmetic number, because the mean of its divisors is an integer number (2060409).

Almost surely, 2^16991973 is an apocalyptic number.

It is an amenable number.

16991973 is a deficient number, since it is larger than the sum of its proper divisors (7732935).

16991973 is a wasteful number, since it uses less digits than its factorization.

16991973 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13924 (or 13921 counting only the distinct ones).

The product of its digits is 91854, while the sum is 45.

The square root of 16991973 is about 4122.1320939533. The cubic root of 16991973 is about 257.0876827390.

The spelling of 16991973 in words is "sixteen million, nine hundred ninety-one thousand, nine hundred seventy-three".