1561279821120 has 196 divisors, whose sum is σ = 5574147264180. Its totient is φ = 416341223424.

The previous prime is 1561279821083. The next prime is 1561279821121. The reversal of 1561279821120 is 211289721651.

1561279821120 is a `hidden beast` number, since 1 + 5 + 612 + 7 + 9 + 8 + 2 + 1 + 1 + 20 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1051346723904 + 509933097216 = 1025352^2 + 714096^2 .

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 (1561279821121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 3113085 + ... + 3579644.

Almost surely, 2^{1561279821120} is an apocalyptic number.

1561279821120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1561279821120 is an abundant number, since it is smaller than the sum of its proper divisors (4012867443060).

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

1561279821120 is an frugal number, since it uses more digits than its factorization.

1561279821120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6692764 (or 6692739 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 45.

The spelling of 1561279821120 in words is "one trillion, five hundred sixty-one billion, two hundred seventy-nine million, eight hundred twenty-one thousand, one hundred twenty".