19963840 has 56 divisors (see below), whose sum is σ = 51206400. Its totient is φ = 7369728.

The previous prime is 19963837. The next prime is 19963841. The reversal of 19963840 is 4836991.

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 19963793 and 19963802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19963841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1761 + ... + 6559.

It is an arithmetic number, because the mean of its divisors is an integer number (914400).

Almost surely, 2^19963840 is an apocalyptic number.

19963840 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 19963840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25603200).

19963840 is an abundant number, since it is smaller than the sum of its proper divisors (31242560).

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

19963840 is a wasteful number, since it uses less digits than its factorization.

19963840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4829 (or 4819 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 40.

The square root of 19963840 is about 4468.0913150919. The cubic root of 19963840 is about 271.2780740691.

The spelling of 19963840 in words is "nineteen million, nine hundred sixty-three thousand, eight hundred forty".