18929857 has 4 divisors (see below), whose sum is σ = 20043396. Its totient is φ = 17816320.

The previous prime is 18929843. The next prime is 18929863. The reversal of 18929857 is 75892981.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7376656 + 11553201 = 2716^2 + 3399^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18929857 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18929857.

It is not an unprimeable number, because it can be changed into a prime (18929887) 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, 556744 + ... + 556777.

It is an arithmetic number, because the mean of its divisors is an integer number (5010849).

Almost surely, 2^18929857 is an apocalyptic number.

18929857 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

18929857 is a deficient number, since it is larger than the sum of its proper divisors (1113539).

18929857 is a wasteful number, since it uses less digits than its factorization.

18929857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1113538.

The product of its digits is 362880, while the sum is 49.

The square root of 18929857 is about 4350.8455500052. The cubic root of 18929857 is about 266.5113920696.

The spelling of 18929857 in words is "eighteen million, nine hundred twenty-nine thousand, eight hundred fifty-seven".