19939645440 has 1152 divisors, whose sum is σ = 86930625600. Its totient is φ = 4152360960.

The previous prime is 19939645373. The next prime is 19939645459. The reversal of 19939645440 is 4454693991.

It is a happy number.

19939645440 is a `hidden beast` number, since 1 + 9 + 9 + 3 + 96 + 4 + 544 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1152).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 224040916 + ... + 224041004.

Almost surely, 2^19939645440 is an apocalyptic number.

19939645440 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 19939645440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43465312800).

19939645440 is an abundant number, since it is smaller than the sum of its proper divisors (66990980160).

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

19939645440 is a wasteful number, since it uses less digits than its factorization.

19939645440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163 (or 140 counting only the distinct ones).

The product of its (nonzero) digits is 4199040, while the sum is 54.

The spelling of 19939645440 in words is "nineteen billion, nine hundred thirty-nine million, six hundred forty-five thousand, four hundred forty".