18913729 has 4 divisors (see below), whose sum is σ = 19062784. Its totient is φ = 18764676.

The previous prime is 18913717. The next prime is 18913733. The reversal of 18913729 is 92731981.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 92731981 = 113 ⋅820637.

It is a cyclic number.

It is not a de Polignac number, because 18913729 - 2²³ = 10525121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18913691 and 18913700.

It is not an unprimeable number, because it can be changed into a prime (18913709) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 74337 + ... + 74590.

It is an arithmetic number, because the mean of its divisors is an integer number (4765696).

Almost surely, 2^18913729 is an apocalyptic number.

It is an amenable number.

18913729 is a deficient number, since it is larger than the sum of its proper divisors (149055).

18913729 is a wasteful number, since it uses less digits than its factorization.

18913729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149054.

The product of its digits is 27216, while the sum is 40.

The square root of 18913729 is about 4348.9917222271. The cubic root of 18913729 is about 266.4356824466.

The spelling of 18913729 in words is "eighteen million, nine hundred thirteen thousand, seven hundred twenty-nine".