1661255623260 has 144 divisors (see below), whose sum is σ = 5063514936480. Its totient is φ = 440861368320.

The previous prime is 1661255623259. The next prime is 1661255623267. The reversal of 1661255623260 is 623265521661.

1661255623260 is a `hidden beast` number, since 1 + 6 + 6 + 1 + 2 + 556 + 2 + 32 + 60 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661255623267) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 67356811 + ... + 67381469.

It is an arithmetic number, because the mean of its divisors is an integer number (35163298170).

Almost surely, 2^{1661255623260} is an apocalyptic number.

1661255623260 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 1661255623260, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2531757468240).

1661255623260 is an abundant number, since it is smaller than the sum of its proper divisors (3402259313220).

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

1661255623260 is a wasteful number, since it uses less digits than its factorization.

1661255623260 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26468 (or 26463 counting only the distinct ones).

The product of its (nonzero) digits is 777600, while the sum is 45.

The spelling of 1661255623260 in words is "one trillion, six hundred sixty-one billion, two hundred fifty-five million, six hundred twenty-three thousand, two hundred sixty".