18520424 has 32 divisors (see below), whose sum is σ = 38415720. Its totient is φ = 8315136.

The previous prime is 18520417. The next prime is 18520427. The reversal of 18520424 is 42402581.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 17556100 + 964324 = 4190^2 + 982^2 .

It is a super-2 number, since 2×18520424² = 686012210279552, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a junction number, because it is equal to n+sod(n) for n = 18520393 and 18520402.

It is not an unprimeable number, because it can be changed into a prime (18520427) 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 7 ways as a sum of consecutive naturals, for example, 1442 + ... + 6254.

Almost surely, 2^18520424 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18520424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (19207860).

18520424 is an abundant number, since it is smaller than the sum of its proper divisors (19895296).

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

18520424 is a wasteful number, since it uses less digits than its factorization.

18520424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4869 (or 4865 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 26.

The square root of 18520424 is about 4303.5362203658. The cubic root of 18520424 is about 264.5759159734.

The spelling of 18520424 in words is "eighteen million, five hundred twenty thousand, four hundred twenty-four".