91944618561 has 16 divisors (see below), whose sum is σ = 136252945920. Its totient is φ = 61278999120.

The previous prime is 91944618559. The next prime is 91944618613. The reversal of 91944618561 is 16581644919.

91944618561 is a `hidden beast` number, since 9 + 19 + 4 + 4 + 61 + 8 + 561 = 666.

It is not a de Polignac number, because 91944618561 - 2¹ = 91944618559 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 91944618498 and 91944618507.

It is not an unprimeable number, because it can be changed into a prime (91944618551) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 386545 + ... + 577326.

It is an arithmetic number, because the mean of its divisors is an integer number (8515809120).

Almost surely, 2^91944618561 is an apocalyptic number.

It is an amenable number.

91944618561 is a deficient number, since it is larger than the sum of its proper divisors (44308327359).

91944618561 is a wasteful number, since it uses less digits than its factorization.

91944618561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 967413 (or 967407 counting only the distinct ones).

The product of its digits is 1866240, while the sum is 54.

The spelling of 91944618561 in words is "ninety-one billion, nine hundred forty-four million, six hundred eighteen thousand, five hundred sixty-one".