66204342561 has 16 divisors (see below), whose sum is σ = 100905305984. Its totient is φ = 37822616064.

The previous prime is 66204342541. The next prime is 66204342601. The reversal of 66204342561 is 16524340266.

It is not a de Polignac number, because 66204342561 - 2³⁰ = 65130600737 is a prime.

It is a super-4 number, since 4×66204342561⁴ (a number of 44 digits) contains 4444 as substring.

It is not an unprimeable number, because it can be changed into a prime (66204342541) 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, 254506 + ... + 444051.

It is an arithmetic number, because the mean of its divisors is an integer number (6306581624).

Almost surely, 2^66204342561 is an apocalyptic number.

It is an amenable number.

66204342561 is a deficient number, since it is larger than the sum of its proper divisors (34700963423).

66204342561 is a wasteful number, since it uses less digits than its factorization.

66204342561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 703080.

The product of its (nonzero) digits is 207360, while the sum is 39.

The spelling of 66204342561 in words is "sixty-six billion, two hundred four million, three hundred forty-two thousand, five hundred sixty-one".