18689953 has 4 divisors (see below), whose sum is σ = 19789380. Its totient is φ = 17590528.

The previous prime is 18689947. The next prime is 18689959. The reversal of 18689953 is 35998681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 35998681 = 541 ⋅66541.

It is an interprime number because it is at equal distance from previous prime (18689947) and next prime (18689959).

It can be written as a sum of positive squares in 2 ways, for example, as 10093329 + 8596624 = 3177^2 + 2932^2 .

It is a cyclic number.

It is not a de Polignac number, because 18689953 - 2⁹ = 18689441 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18689897 and 18689906.

It is not an unprimeable number, because it can be changed into a prime (18689959) by changing a digit.

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

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 549688 + ... + 549721.

It is an arithmetic number, because the mean of its divisors is an integer number (4947345).

Almost surely, 2^18689953 is an apocalyptic number.

It is an amenable number.

18689953 is a deficient number, since it is larger than the sum of its proper divisors (1099427).

18689953 is a wasteful number, since it uses less digits than its factorization.

18689953 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1099426.

The product of its digits is 466560, while the sum is 49.

The square root of 18689953 is about 4323.1878284433. The cubic root of 18689953 is about 265.3807414188.

The spelling of 18689953 in words is "eighteen million, six hundred eighty-nine thousand, nine hundred fifty-three".