19945405440 has 352 divisors, whose sum is σ = 71310274560. Its totient is φ = 5286739968.

The previous prime is 19945405433. The next prime is 19945405451. The reversal of 19945405440 is 4450454991.

19945405440 is a `hidden beast` number, since 19 + 9 + 4 + 540 + 54 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 30827197 + ... + 30827843.

Almost surely, 2^19945405440 is an apocalyptic number.

19945405440 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 19945405440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35655137280).

19945405440 is an abundant number, since it is smaller than the sum of its proper divisors (51364869120).

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

19945405440 is a wasteful number, since it uses less digits than its factorization.

19945405440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 904 (or 880 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 45.

The spelling of 19945405440 in words is "nineteen billion, nine hundred forty-five million, four hundred five thousand, four hundred forty".