66561610205147 has 16 divisors (see below), whose sum is σ = 68628252806400. Its totient is φ = 64532485317600.

The previous prime is 66561610205141. The next prime is 66561610205159. The reversal of 66561610205147 is 74150201616566.

It is a cyclic number.

It is not a de Polignac number, because 66561610205147 - 2²² = 66561606010843 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66561610205095 and 66561610205104.

It is not an unprimeable number, because it can be changed into a prime (66561610205141) 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, 25636748 + ... + 28113449.

It is an arithmetic number, because the mean of its divisors is an integer number (4289265800400).

Almost surely, 2^{66561610205147} is an apocalyptic number.

66561610205147 is a deficient number, since it is larger than the sum of its proper divisors (2066642601253).

66561610205147 is a wasteful number, since it uses less digits than its factorization.

66561610205147 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53750546.

The product of its (nonzero) digits is 1814400, while the sum is 50.

The spelling of 66561610205147 in words is "sixty-six trillion, five hundred sixty-one billion, six hundred ten million, two hundred five thousand, one hundred forty-seven".