19640418640 has 80 divisors (see below), whose sum is σ = 46069337088. Its totient is φ = 7786615808.

The previous prime is 19640418619. The next prime is 19640418649. The reversal of 19640418640 is 4681404691.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19640418649) 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 15 ways as a sum of consecutive naturals, for example, 10772769 + ... + 10774591.

Almost surely, 2^19640418640 is an apocalyptic number.

19640418640 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 19640418640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23034668544).

19640418640 is an abundant number, since it is smaller than the sum of its proper divisors (26428918448).

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

19640418640 is a wasteful number, since it uses less digits than its factorization.

19640418640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2956 (or 2950 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 43.

The spelling of 19640418640 in words is "nineteen billion, six hundred forty million, four hundred eighteen thousand, six hundred forty".