18428729 has 4 divisors (see below), whose sum is σ = 20104080. Its totient is φ = 16753380.

The previous prime is 18428719. The next prime is 18428737. The reversal of 18428729 is 92782481.

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.

It is a cyclic number.

It is not a de Polignac number, because 18428729 - 2⁴ = 18428713 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18428719) 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, 837659 + ... + 837680.

It is an arithmetic number, because the mean of its divisors is an integer number (5026020).

Almost surely, 2^18428729 is an apocalyptic number.

It is an amenable number.

18428729 is a deficient number, since it is larger than the sum of its proper divisors (1675351).

18428729 is a wasteful number, since it uses less digits than its factorization.

18428729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1675350.

The product of its digits is 64512, while the sum is 41.

The square root of 18428729 is about 4292.8695531078. The cubic root of 18428729 is about 264.1385531133.

The spelling of 18428729 in words is "eighteen million, four hundred twenty-eight thousand, seven hundred twenty-nine".