66561636340044 has 48 divisors (see below), whose sum is σ = 172829067734400. Its totient is φ = 22153544089488.

The previous prime is 66561636340013. The next prime is 66561636340079. The reversal of 66561636340044 is 44004363616566.

66561636340044 is a `hidden beast` number, since 6 + 6 + 561 + 6 + 3 + 6 + 34 + 0 + 0 + 44 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 467539942 + ... + 467682285.

It is an arithmetic number, because the mean of its divisors is an integer number (3600605577800).

Almost surely, 2^{66561636340044} is an apocalyptic number.

It is an amenable number.

66561636340044 is an abundant number, since it is smaller than the sum of its proper divisors (106267431394356).

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

66561636340044 is a wasteful number, since it uses less digits than its factorization.

66561636340044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 935222899 (or 935222891 counting only the distinct ones).

The product of its (nonzero) digits is 22394880, while the sum is 54.

The spelling of 66561636340044 in words is "sixty-six trillion, five hundred sixty-one billion, six hundred thirty-six million, three hundred forty thousand, forty-four".