18691429 has 4 divisors (see below), whose sum is σ = 18863020. Its totient is φ = 18519840.

The previous prime is 18691427. The next prime is 18691441. The reversal of 18691429 is 92419681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 92419681 = 23 ⋅4018247.

It can be written as a sum of positive squares in 2 ways, for example, as 11390625 + 7300804 = 3375^2 + 2702^2 .

It is a cyclic number.

It is not a de Polignac number, because 18691429 - 2¹ = 18691427 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18691391 and 18691400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18691423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is an upside-down number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85632 + ... + 85849.

It is an arithmetic number, because the mean of its divisors is an integer number (4715755).

Almost surely, 2^18691429 is an apocalyptic number.

It is an amenable number.

18691429 is a deficient number, since it is larger than the sum of its proper divisors (171591).

18691429 is a wasteful number, since it uses less digits than its factorization.

18691429 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171590.

The product of its digits is 31104, while the sum is 40.

The square root of 18691429 is about 4323.3585324375. The cubic root of 18691429 is about 265.3877271981.

The spelling of 18691429 in words is "eighteen million, six hundred ninety-one thousand, four hundred twenty-nine".