19816940 has 96 divisors (see below), whose sum is σ = 50379840. Its totient is φ = 6489600.

The previous prime is 19816933. The next prime is 19816987. The reversal of 19816940 is 4961891.

It is a happy number.

It is a super-2 number, since 2×19816940² = 785422221927200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 19816894 and 19816903.

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 31 ways as a sum of consecutive naturals, for example, 483320 + ... + 483360.

It is an arithmetic number, because the mean of its divisors is an integer number (524790).

Almost surely, 2^19816940 is an apocalyptic number.

19816940 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 19816940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25189920).

19816940 is an abundant number, since it is smaller than the sum of its proper divisors (30562900).

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

19816940 is a wasteful number, since it uses less digits than its factorization.

19816940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100 (or 72 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 19816940 is about 4451.6221762409. The cubic root of 19816940 is about 270.6110531742.

The spelling of 19816940 in words is "nineteen million, eight hundred sixteen thousand, nine hundred forty".