1305661399680 has 384 divisors, whose sum is σ = 4578577093440. Its totient is φ = 316244459520.

The previous prime is 1305661399673. The next prime is 1305661399687. The reversal of 1305661399680 is 869931665031.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1305661399673) and next prime (1305661399687).

It is a tau number, because it is divible by the number of its divisors (384).

It is a super-2 number, since 2×1305661399680² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1305661399680.

It is not an unprimeable number, because it can be changed into a prime (1305661399687) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 405861432 + ... + 405864648.

Almost surely, 2^{1305661399680} is an apocalyptic number.

1305661399680 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 1305661399680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2289288546720).

1305661399680 is an abundant number, since it is smaller than the sum of its proper divisors (3272915693760).

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

1305661399680 is a wasteful number, since it uses less digits than its factorization.

1305661399680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5008 (or 4985 counting only the distinct ones).

The product of its (nonzero) digits is 6298560, while the sum is 57.

The spelling of 1305661399680 in words is "one trillion, three hundred five billion, six hundred sixty-one million, three hundred ninety-nine thousand, six hundred eighty".