19729917 has 24 divisors (see below), whose sum is σ = 29521440. Its totient is φ = 12687840.

The previous prime is 19729909. The next prime is 19729933. The reversal of 19729917 is 71992791.

It is not a de Polignac number, because 19729917 - 2³ = 19729909 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19729907) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 59442 + ... + 59772.

It is an arithmetic number, because the mean of its divisors is an integer number (1230060).

Almost surely, 2^19729917 is an apocalyptic number.

It is an amenable number.

19729917 is a deficient number, since it is larger than the sum of its proper divisors (9791523).

19729917 is a wasteful number, since it uses less digits than its factorization.

19729917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 553 (or 550 counting only the distinct ones).

The product of its digits is 71442, while the sum is 45.

The square root of 19729917 is about 4441.8371199313. The cubic root of 19729917 is about 270.2143565235.

The spelling of 19729917 in words is "nineteen million, seven hundred twenty-nine thousand, nine hundred seventeen".