18646420 has 48 divisors (see below), whose sum is σ = 43641360. Its totient is φ = 6644736.

The previous prime is 18646417. The next prime is 18646423. The reversal of 18646420 is 2464681.

It is an interprime number because it is at equal distance from previous prime (18646417) and next prime (18646423).

It can be written as a sum of positive squares in 8 ways, for example, as 293764 + 18352656 = 542^2 + 4284^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18646423) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6304 + ... + 8776.

It is an arithmetic number, because the mean of its divisors is an integer number (909195).

Almost surely, 2^18646420 is an apocalyptic number.

18646420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18646420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21820680).

18646420 is an abundant number, since it is smaller than the sum of its proper divisors (24994940).

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

18646420 is a wasteful number, since it uses less digits than its factorization.

18646420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2524 (or 2522 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 31.

The square root of 18646420 is about 4318.1500668689. The cubic root of 18646420 is about 265.1745379196.

The spelling of 18646420 in words is "eighteen million, six hundred forty-six thousand, four hundred twenty".