1978199240640 has 448 divisors, whose sum is σ = 7277336524800. Its totient is φ = 445931126784.

The previous prime is 1978199240639. The next prime is 1978199240663. The reversal of 1978199240640 is 460429918791.

It is a tau number, because it is divible by the number of its divisors (448).

It is a Harshad number since it is a multiple of its sum of digits (60).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 244610677 + ... + 244618763.

Almost surely, 2^{1978199240640} is an apocalyptic number.

1978199240640 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 1978199240640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3638668262400).

1978199240640 is an abundant number, since it is smaller than the sum of its proper divisors (5299137284160).

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

1978199240640 is a wasteful number, since it uses less digits than its factorization.

1978199240640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8612 (or 8602 counting only the distinct ones).

The product of its (nonzero) digits is 7838208, while the sum is 60.

The spelling of 1978199240640 in words is "one trillion, nine hundred seventy-eight billion, one hundred ninety-nine million, two hundred forty thousand, six hundred forty".