84131385561 has 40 divisors (see below), whose sum is σ = 133448298984. Its totient is φ = 52638474240.

The previous prime is 84131385557. The next prime is 84131385571. The reversal of 84131385561 is 16558313148.

84131385561 is a `hidden beast` number, since 8 + 4 + 1 + 3 + 1 + 3 + 85 + 561 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 49477329225 + 34654056336 = 222435^2 + 186156^2 .

It is not a de Polignac number, because 84131385561 - 2² = 84131385557 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (84131385571) 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 39 ways as a sum of consecutive naturals, for example, 399541 + ... + 572621.

Almost surely, 2^84131385561 is an apocalyptic number.

84131385561 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

84131385561 is a deficient number, since it is larger than the sum of its proper divisors (49316913423).

84131385561 is a wasteful number, since it uses less digits than its factorization.

84131385561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173463 (or 173454 counting only the distinct ones).

The product of its digits is 345600, while the sum is 45.

The spelling of 84131385561 in words is "eighty-four billion, one hundred thirty-one million, three hundred eighty-five thousand, five hundred sixty-one".