18687420 has 144 divisors (see below), whose sum is σ = 62270208. Its totient is φ = 4515840.

The previous prime is 18687407. The next prime is 18687433. The reversal of 18687420 is 2478681.

It is an interprime number because it is at equal distance from previous prime (18687407) and next prime (18687433).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 94762 + ... + 94958.

It is an arithmetic number, because the mean of its divisors is an integer number (432432).

Almost surely, 2^18687420 is an apocalyptic number.

18687420 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 18687420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31135104).

18687420 is an abundant number, since it is smaller than the sum of its proper divisors (43582788).

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

18687420 is a wasteful number, since it uses less digits than its factorization.

18687420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260 (or 255 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 18687420 is about 4322.8948633988. The cubic root of 18687420 is about 265.3687520933.

The spelling of 18687420 in words is "eighteen million, six hundred eighty-seven thousand, four hundred twenty".