18947820 has 96 divisors (see below), whose sum is σ = 55996416. Its totient is φ = 4780800.

The previous prime is 18947813. The next prime is 18947827. The reversal of 18947820 is 2874981.

It is an interprime number because it is at equal distance from previous prime (18947813) and next prime (18947827).

It is not an unprimeable number, because it can be changed into a prime (18947827) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 113377 + ... + 113543.

It is an arithmetic number, because the mean of its divisors is an integer number (583296).

Almost surely, 2^18947820 is an apocalyptic number.

18947820 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 18947820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27998208).

18947820 is an abundant number, since it is smaller than the sum of its proper divisors (37048596).

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

18947820 is a wasteful number, since it uses less digits than its factorization.

18947820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 271 (or 269 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 39.

The square root of 18947820 is about 4352.9093719029. The cubic root of 18947820 is about 266.5956651249.

The spelling of 18947820 in words is "eighteen million, nine hundred forty-seven thousand, eight hundred twenty".