1961377091856 has 240 divisors, whose sum is σ = 6771124703616. Its totient is φ = 516117049344.

The previous prime is 1961377091813. The next prime is 1961377091879. The reversal of 1961377091856 is 6581907731691.

1961377091856 is a `hidden beast` number, since 1 + 9 + 613 + 7 + 7 + 0 + 9 + 1 + 8 + 5 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a junction number, because it is equal to n+sod(n) for n = 1961377091793 and 1961377091802.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5636136 + ... + 5974008.

Almost surely, 2^{1961377091856} is an apocalyptic number.

1961377091856 is a gapful number since it is divisible by the number (16) 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 1961377091856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3385562351808).

1961377091856 is an abundant number, since it is smaller than the sum of its proper divisors (4809747611760).

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

1961377091856 is a wasteful number, since it uses less digits than its factorization.

1961377091856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 338350 (or 338341 counting only the distinct ones).

The product of its (nonzero) digits is 17146080, while the sum is 63.

The spelling of 1961377091856 in words is "one trillion, nine hundred sixty-one billion, three hundred seventy-seven million, ninety-one thousand, eight hundred fifty-six".