19618820 has 48 divisors (see below), whose sum is σ = 45132528. Its totient is φ = 7119360.

The previous prime is 19618817. The next prime is 19618829. The reversal of 19618820 is 2881691.

It can be written as a sum of positive squares in 8 ways, for example, as 3474496 + 16144324 = 1864^2 + 4018^2 .

It is not an unprimeable number, because it can be changed into a prime (19618829) 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, 15242 + ... + 16478.

It is an arithmetic number, because the mean of its divisors is an integer number (940261).

Almost surely, 2^19618820 is an apocalyptic number.

19618820 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 19618820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22566264).

19618820 is an abundant number, since it is smaller than the sum of its proper divisors (25513708).

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

19618820 is a wasteful number, since it uses less digits than its factorization.

19618820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1320 (or 1318 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 35.

The square root of 19618820 is about 4429.3137165931. The cubic root of 19618820 is about 269.7062190970.

The spelling of 19618820 in words is "nineteen million, six hundred eighteen thousand, eight hundred twenty".