19864926640 has 80 divisors (see below), whose sum is σ = 50203849248. Its totient is φ = 7266152448.

The previous prime is 19864926623. The next prime is 19864926671. The reversal of 19864926640 is 4662946891.

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

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 15 ways as a sum of consecutive naturals, for example, 22024 + ... + 200536.

Almost surely, 2^19864926640 is an apocalyptic number.

19864926640 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 19864926640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25101924624).

19864926640 is an abundant number, since it is smaller than the sum of its proper divisors (30338922608).

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

19864926640 is a wasteful number, since it uses less digits than its factorization.

19864926640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178646 (or 178640 counting only the distinct ones).

The product of its (nonzero) digits is 4478976, while the sum is 55.

The spelling of 19864926640 in words is "nineteen billion, eight hundred sixty-four million, nine hundred twenty-six thousand, six hundred forty".