1961979797500 has 60 divisors (see below), whose sum is σ = 4291977908680. Its totient is φ = 784513800000.

The previous prime is 1961979797471. The next prime is 1961979797509. The reversal of 1961979797500 is 57979791691.

It is a self number, because there is not a number n which added to its sum of digits gives 1961979797500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1961979797509) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6989866 + ... + 7265134.

Almost surely, 2^{1961979797500} is an apocalyptic number.

1961979797500 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 1961979797500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2145988954340).

1961979797500 is an abundant number, since it is smaller than the sum of its proper divisors (2329998111180).

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

1961979797500 is a wasteful number, since it uses less digits than its factorization.

1961979797500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 278144 (or 278127 counting only the distinct ones).

The product of its (nonzero) digits is 67512690, while the sum is 70.

The spelling of 1961979797500 in words is "one trillion, nine hundred sixty-one billion, nine hundred seventy-nine million, seven hundred ninety-seven thousand, five hundred".