1979781699840 has 864 divisors, whose sum is σ = 7573877498880. Its totient is φ = 439206985728.

The previous prime is 1979781699839. The next prime is 1979781699851. The reversal of 1979781699840 is 489961879791.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1448266837 + ... + 1448268203.

It is an arithmetic number, because the mean of its divisors is an integer number (8766061920).

Almost surely, 2^{1979781699840} is an apocalyptic number.

1979781699840 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 1979781699840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3786938749440).

1979781699840 is an abundant number, since it is smaller than the sum of its proper divisors (5594095799040).

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

1979781699840 is a wasteful number, since it uses less digits than its factorization.

1979781699840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1627 (or 1606 counting only the distinct ones).

The product of its (nonzero) digits is 493807104, while the sum is 78.

The spelling of 1979781699840 in words is "one trillion, nine hundred seventy-nine billion, seven hundred eighty-one million, six hundred ninety-nine thousand, eight hundred forty".