1561982965920 has 576 divisors, whose sum is σ = 5978057589504. Its totient is φ = 382862868480.

The previous prime is 1561982965919. The next prime is 1561982965979. The reversal of 1561982965920 is 295692891651.

1561982965920 is a `hidden beast` number, since 1 + 5 + 6 + 19 + 8 + 29 + 6 + 592 + 0 = 666.

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, 121804629 + ... + 121817451.

It is an arithmetic number, because the mean of its divisors is an integer number (10378572204).

Almost surely, 2^{1561982965920} is an apocalyptic number.

1561982965920 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 1561982965920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2989028794752).

1561982965920 is an abundant number, since it is smaller than the sum of its proper divisors (4416074623584).

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

1561982965920 is a wasteful number, since it uses less digits than its factorization.

1561982965920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13107 (or 13087 counting only the distinct ones).

The product of its (nonzero) digits is 20995200, while the sum is 63.

The spelling of 1561982965920 in words is "one trillion, five hundred sixty-one billion, nine hundred eighty-two million, nine hundred sixty-five thousand, nine hundred twenty".