1643351063940 has 672 divisors, whose sum is σ = 5679578459520. Its totient is φ = 397746505728.

The previous prime is 1643351063899. The next prime is 1643351063941. The reversal of 1643351063940 is 493601533461.

It is a happy number.

1643351063940 is a `hidden beast` number, since 1 + 6 + 4 + 3 + 3 + 5 + 1 + 0 + 639 + 4 + 0 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (1643351063941) by changing a digit.

It is a polite number, since it can be written in 223 ways as a sum of consecutive naturals, for example, 686731384 + ... + 686733776.

It is an arithmetic number, because the mean of its divisors is an integer number (8451753660).

Almost surely, 2^{1643351063940} is an apocalyptic number.

1643351063940 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 1643351063940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2839789229760).

1643351063940 is an abundant number, since it is smaller than the sum of its proper divisors (4036227395580).

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

1643351063940 is a wasteful number, since it uses less digits than its factorization.

1643351063940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2543 (or 2526 counting only the distinct ones).

The product of its (nonzero) digits is 699840, while the sum is 45.

The spelling of 1643351063940 in words is "one trillion, six hundred forty-three billion, three hundred fifty-one million, sixty-three thousand, nine hundred forty".