19997929 has 10 divisors (see below), whose sum is σ = 23332330. Its totient is φ = 17139024.

The previous prime is 19997911. The next prime is 19997953. The reversal of 19997929 is 92979991.

It can be written as a sum of positive squares in only one way, i.e., 13505625 + 6492304 = 3675^2 + 2548^2 .

It is not a de Polignac number, because 19997929 - 2⁵ = 19997897 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19997929.

It is not an unprimeable number, because it can be changed into a prime (19997129) 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 9 ways as a sum of consecutive naturals, for example, 1764 + ... + 6565.

It is an arithmetic number, because the mean of its divisors is an integer number (2333233).

Almost surely, 2^19997929 is an apocalyptic number.

It is an amenable number.

19997929 is a deficient number, since it is larger than the sum of its proper divisors (3334401).

19997929 is an frugal number, since it uses more digits than its factorization.

19997929 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8357 (or 8336 counting only the distinct ones).

The product of its digits is 826686, while the sum is 55.

The square root of 19997929 is about 4471.9044041661. The cubic root of 19997929 is about 271.4323920713.

The spelling of 19997929 in words is "nineteen million, nine hundred ninety-seven thousand, nine hundred twenty-nine".