1261989496320 has 960 divisors, whose sum is σ = 4824456215040. Its totient is φ = 280497487872.

The previous prime is 1261989496319. The next prime is 1261989496337. The reversal of 1261989496320 is 236949891621.

It is a tau number, because it is divible by the number of its divisors (960).

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 (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2508925189 + ... + 2508925691.

It is an arithmetic number, because the mean of its divisors is an integer number (5025475224).

Almost surely, 2^{1261989496320} is an apocalyptic number.

1261989496320 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 1261989496320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2412228107520).

1261989496320 is an abundant number, since it is smaller than the sum of its proper divisors (3562466718720).

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

1261989496320 is a wasteful number, since it uses less digits than its factorization.

1261989496320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 715 (or 692 counting only the distinct ones).

The product of its (nonzero) digits is 10077696, while the sum is 60.

The spelling of 1261989496320 in words is "one trillion, two hundred sixty-one billion, nine hundred eighty-nine million, four hundred ninety-six thousand, three hundred twenty".