19685820 has 96 divisors (see below), whose sum is σ = 68737536. Its totient is φ = 4089600.

The previous prime is 19685819. The next prime is 19685833. The reversal of 19685820 is 2858691.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2490 + ... + 6750.

It is an arithmetic number, because the mean of its divisors is an integer number (716016).

Almost surely, 2^19685820 is an apocalyptic number.

19685820 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 19685820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34368768).

19685820 is an abundant number, since it is smaller than the sum of its proper divisors (49051716).

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

19685820 is a wasteful number, since it uses less digits than its factorization.

19685820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4291 (or 4289 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 39.

The square root of 19685820 is about 4436.8705187328. The cubic root of 19685820 is about 270.0128937601.

It can be divided in two parts, 196858 and 20, that added together give a triangular number (196878 = T₆₂₇).

The spelling of 19685820 in words is "nineteen million, six hundred eighty-five thousand, eight hundred twenty".