18690438 has 32 divisors (see below), whose sum is σ = 40755456. Its totient is φ = 5679648.

The previous prime is 18690437. The next prime is 18690449. The reversal of 18690438 is 83409681.

It is a super-3 number, since 3×18690438³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a junction number, because it is equal to n+sod(n) for n = 18690396 and 18690405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18690431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5031 + ... + 7917.

It is an arithmetic number, because the mean of its divisors is an integer number (1273608).

Almost surely, 2^18690438 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18690438, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20377728).

18690438 is an abundant number, since it is smaller than the sum of its proper divisors (22065018).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18690438 is a wasteful number, since it uses less digits than its factorization.

18690438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2988.

The product of its (nonzero) digits is 41472, while the sum is 39.

The square root of 18690438 is about 4323.2439209464. The cubic root of 18690438 is about 265.3830369221.

The spelling of 18690438 in words is "eighteen million, six hundred ninety thousand, four hundred thirty-eight".